2-Propenoic acid, 2-propylheptyl ester

Toxicity to reproduction

Administrative data

Endpoint:

two-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2008-04-21 to 2009-09-09

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-study according to OECD guideline 416. Read across was performed with methyl acrylate. Please refer to IUCLID section 13 for read across justification.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)

Version / remarks:

2001

Deviations:

yes

Principles of method if other than guideline:

Anogenital distance, a triggered end point as per test guidelines, was not measured in the F2 pups because there were no significant effects observed on F1 sex ratio or age at vaginal opening or preputial separation.

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Methyl acrylate

EC Number:

202-500-6

EC Name:

Methyl acrylate

Cas Number:

96-33-3

IUPAC Name:

methyl acrylate

Test material form:

other: liquid

Details on test material:

Test material name: Methyl acrylate
Chemical name: 2-Propenoic acid methyl ester
Synonyms: Acrylic acid methyl ester, Methyl-2-propenoate
Source: The Dow Chemical Company, Bayport, Texas
Reference: Lot: VF1301RFM1
Purity: 99.9%
Appearance: Colorless liquid
Vapor Pressure: 68 mm Hg at 20°C
Odor: Acrid odor
Molecular Formula: C4H6O2
Molecular Weight: 86.1

Test animals

Species:

rat

Strain:

other: Crl:CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories Inc. (Portage, Michigan)
- Age at study initiation: (P) 6 wks; (F1) x wks
- Mean weight at study initiation: (P) Males: 176.9 ± 6.3 g; Females: 131.0 ± 5.8 g; (F1) Males: 169.7 ± 22.8 g; Females: 143.6 ± 16.8 g
- Fasting period before study: no
- Housing: singly in stainless steel cages, except during breeding (one male and female)
- Use of restrainers for preventing ingestion (if dermal): no
- Diet: LabDiet Certified Rodent Diet #5002 (PMI Nutrition International, St. Louis, Missouri), ad libitum
- Water: drinking water from the municipal water source, ad libitum
- Acclimation period: at least one week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 1
- Humidity (%): 40 - 70
- Air changes (per hr): 12-15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure (if applicable):

whole body

Vehicle:

other: air

Details on exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 14.5 m^3 inhalation exposure chambers under dynamic airflow conditions
- System of generating aerosols: generated by using the J-tube method of Miller et al.
- Temperature, humidity in air chamber: 22 ± 2°C, 40 to 60%
- Air flow rate: 2900 L/min
- Method of particle size determination:
- Treatment of exhaust air: All test chamber exhaust was passed through an activated charcoal bed to remove test material from the exhaust stream.

TEST ATMOSPHERE
- Brief description of analytical method used: An IR spectrophotometer was used to evaluate the chamber concentrations.
- Samples taken from breathing zone: yes, once per hour

Details on mating procedure:

- M/F ratio per cage: 1/1
- Length of cohabitation: until mating occurred or two weeks elapsed
- Proof of pregnancy: vaginal plug, sperm in vaginal smear referred to as day 0 of pregnancy
- Further matings after one unsuccessful attempt: no
- After successful mating each pregnant female was caged (how): in stailess steel cages

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The chamber concentrations of methyl acrylate, measured approximately in the center of the breathing zone of the animals, were determined at least once per hour with a Miran 1A infrared (IR) spectrophotometer (Foxboro/Wilks, South Norwalk, Connecticut) and reported by a strip chart recorder. The IR spectrophotometer was calibrated and a standard curve was compiled prior to and at the midpoint of the study, using air standards prepared by vaporizing measured volumes of methyl acrylate into Tedlar sample bags (Series 233, SKC, Eighty Four, Pennsylvania) along with the metered volumes of dry, compressed air. Chamber concentrations during the exposures were interpolated using the standard curve. The analytical system was checked prior to each exposure with a methyl acrylate standard gasbag of known concentration. The CAMILE TG 4 Data Acquisition and Control System toggled the IR spectrophotometer between the chambers for concentration sampling. The nominal concentration of the test material in each chamber was estimated based on the amount of test material used and the total airflow through the chamber. Prior to the start of the study, each of the chambers was checked to ensure that a uniform distribution of vapor was present throughout the breathing zone of the animals.

Duration of treatment / exposure:

6 hours/day, 7 days/week for approximately 10 weeks prior to breeding and continuing through breeding (two weeks), gestation (three weeks) and lactation (four weeks) for each of two generations

Frequency of treatment:

Daily. Maternal rats were not exposed to methyl acrylate after Gestation Day (GD) 20 through Lactation Day (LD) 4 in order to allow for parturition and initiation of lactation.

Details on study schedule:

- F1 parental animals not mated at least until 10 weeks after selected from the F1 litters.
- Selection of parents from F1 generation when pups were 28 days of age.
- Age at mating of the mated animals in the study: approx. 13 weeks

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
0, 5, 25, and 75 ppm
Basis:
other: target concentration

Doses / concentrations 2

Remarks:

Doses / Concentrations:
0, 5.3 ± 0.2, 24.9 ± 0.4, and 73.4 ± 1.8 ppm
Basis:
nominal conc.

Doses / concentrations 3

Remarks:

Doses / Concentrations:
0, 5.3 ± 0.2, 25.7 ± 0.3, and 75.4 ± 0.6 ppm (corresponding to approx. 0, 0.019, 0.092, and 0.269 mg/L)
Basis:
analytical conc.
Recalculation based on the equation c(mg/m3) = molar mass (g) / molar volume (L) x c(mL/m3) with molecular weight (86.09 g/mol) and molar volume (24.1 L at 20 °C and 1013 hPa) [DFG, 2005]

No. of animals per sex per dose:

27/sex/dose

Control animals:

yes, sham-exposed

Details on study design:

- Dose selection rationale: Two other developmental toxicity tests (Saillenfait et al. 1999; Carney et al., 2008) with methyl acrylate were used for dose selection.

Positive control:

None

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly (males and females) throughout breeding period; mated females on GD 0, 7, 14, 21 and LD 0, 1, 4, 7, 14, 21, 28

BODY WEIGHT: Yes
- Time schedule for examinations: males and females were weighed weekly; mated females on GD 0, 7, 14, 21 and on LD 1, 4, 7, 14, 21, 28

FOOD CONSUMPTION AND COMPOUND INTAKE: Yes
- Time schedule: weekly (males and females) throughout breeding period; mated females on GD 0, 7, 14, 21 and on LD 1, 4, 7, 14, 21, 23, 26, 28

Oestrous cyclicity (parental animals):

Vaginal lavage samples were collected daily for all P1 and P2 females for three weeks prior to mating and during cohabitation until each female was sperm or plug positive or until the two-week mating period elapsed. Lavage samples were collected by gently irrigating the vagina with water and transferring loosely adherent vaginal cells to a slide with a pipette. Vaginal lavage slides were examined to determine estrous cycle length and pattern. Additionally, on the day of scheduled necropsy, the stage within the estrous cycle was determined for all P1 and P2 female rats.

Sperm parameters (parental animals):

Parameters examined in P1, P2 male parental generations:
testis weight, epididymis weight, sperm count in testes, sperm count in epididymides, enumeration of cauda epididymal sperm reserve, sperm motility, sperm morphology

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: yes
- If yes, maximum of 8 pups/litter (4/sex/litter as nearly as possible); excess pups were killed and discarded.

PARAMETERS EXAMINED
The following parameters were examined in P1 / P2 offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical or behavioural abnormalities

GROSS EXAMINATION OF DEAD PUPS:
yes, for external and internal abnormalities; possible cause of death was not determined for pups born or found dead.

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals were sacrificed after completion of their respective mating period.
- Maternal animals: All surviving animals were sacrificed after weaning of their litters or at least 24 days after the end of the mating period for females not producing a litter.

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.

HISTOPATHOLOGY / ORGAN WEIGHTS
Weights of the ovaries, uterus (with oviducts and cervix), testes, epididymides, seminal vesicles with coagulating glands (and fluids), prostate, brain, pituitary (weighed after fixation), liver, kidneys, adrenal glands, spleen, thyroid with parathyroids (weighed after fixation) were recorded, and the organ-to-body weight ratios calculated. In addition, weights of the left testis and left cauda epididymis were collected for use in calculating sperm count parameters.

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring not selected as parental animals and all F2 offspring were sacrificed at 28 days of age.

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.

HISTOPATHOLOGY / ORGAN WEIGTHS
Representative sample of grossly abnormal tissues and any known target organs were collected from all weanlings at the scheduled necropsy. In addition, one of the three pups/sex/litter was randomly selected from those examined grossly for the collection of brain, spleen, uterus, and thymus weights. Organ-to-body weight ratios were calculated. The brain, spleen, thymus, gross lesions and known target organs were preserved in neutral, phosphate-buffered 10% formalin. Dead or moribund pups were examined in a similar manner for possible defects and/or cause of death and were preserved in neutral, phosphate-buffered 10% formalin.

Statistics:

See below "Any other information on material and methods"

Reproductive indices:

Reproductive indices were calculated for all dose level groups as follows:
• Female mating index = (No. females with evidence of mating/No. paired) x 100
• Male mating index = (No. males with evidence of mating/No. paired) x 100
• Female conception index = (No. females with evidence of pregnancy/No. mated) x 100
• Male conception index = (No. males siring a litter/No. mated) x 100
• Female fertility index = (No. females with evidence of pregnancy/No. paired) x 100
• Male fertility index = (No. males siring a litter/No. paired) x 100
• Gestation index = (No. females delivering a viable litter/No. females with evidence of pregnancy) x 100
• Gestation survival index = percentage of delivered pups alive at birth
• Post-implantation loss = (No. implants – No. viable offspring)/(No. implants) x 100
• Day 1 or 4 pup survival index = (No. viable pups on day 1 or 4/No. born live) x 100
• Day 7, 14, 21 or 28 pup survival index = (No. viable pups on day 7, 14, 21 or 28/No. live after culling) x 100

Offspring viability indices:

• Day 1 or 4 pup survival index = (No. viable pups on day 1 or 4/No. born live) x 100
• Day 7, 14, 21 or 28 pup survival index = (No. viable pups on day 7, 14, 21 or 28/No. live after culling) x 100

Results and discussion

Results: P0 (first parental generation)

Details on results (P0)

Screening Test- Treatment-related clinical signs in the 150 ppm P1 males and females were limited to a transient sneezing/huffing sound noted each day immediately following the end of exposure, occurring from day 36. This sound was observed until termination of the P1 males. In females, this sound was no longer present when exposure was stopped from GD 21 – LD 4, but was observed again upon resumption of exposure (LD 5-28), albeit at a lesser severity and incidence. P1 males and females exposed to 150 ppm had treatment-related decreases in body weights, body weight gains and feed consumption that were observed during the pre-breeding, gestation and lactation phases. Similar, but less severe effects on body weight and feed consumption were seen in males and females exposed to 75 ppm. There was a dose-dependent decrease in the terminal body weights of rats exposed to methyl acrylate.

There were no treatment-related effects on any reproductive parameters, organ weights, or gross pathology. Dose-related histopathologic effects were present in the nasal tissues of males and females at all exposure concentrations. Degeneration with regeneration of the olfactory epithelium (very slight to severe) occurred in males and females at 150 ppm and in males at 75 ppm. Regenerative hyperplasia of the olfactory epithelium accompanied the degenerative change in multifocal sites. A lesser degree of olfactory epithelial degeneration (very slight), without accompanying regenerative hyperplasia, was noted in females at 75 ppm, and in males and females at 25 ppm. Very slight or slight degeneration of the olfactory nerve was present in males and females at 150 ppm only. Very slight or slight chronic active inflammation accompanied the olfactory epithelial degeneration in males and females at 150 ppm, and in females at 75 ppm. Very slight necrosis of individual olfactory epithelial cells, and multifocal, very slight or slight hyperlasia of the transitional epithelium that covers the nasal turbinates was present in rats exposed to 25, 75, or 150 ppm. There was a slight decrease in the PND 14 body weight of pups whose dams were exposed to 150 ppm methyl acrylate. No clinical signs were observed in the F1 males or females that were exposed from PND 28-35. F1 males and females exposed to 150 ppm had treatment-related decreases in body weights and feed consumption. Similar, but less severe effects on body weight and feed consumption were seen in F1 males and females exposed to 75 ppm.

Percent Difference in Terminal Body Weight Compared to Control
25 ppm 75 ppm 150 ppm
P1 Males -1% -7% -13%
P1 Females -1% -2% -12%
F1 Males +2% -4% -18%
F1 Females -1% -9% -17%

Chamber Concentration
Mean chamber concentration values during the study were 0, 5.3 ± 0.2, 25.7 ± 0.3, and 75.4 ± 0.6 ppm. Actual mean chamber concentration values deviated 0.5-6% from the targeted values of 0, 5, 25, and 75 ppm.

In-Life Observations
Examinations performed on all animals prior to the study start revealed that all animals were in good health for study purposes.

No treatment-related effects on behavior or demeanor were observed in any phase of the study at any dose level. A number of incidental observations bearing no relation to treatment were observed.

Feed Consumption
There was a treatment-related decrease in feed consumption of the P1 males in the 75 ppm exposure group when compared to controls, although these differences only reached statistical significance for three measurement intervals (TD 1-7, 7-14, and 56-63) throughout the first generation. During the 10-week premating period, there was a treatment-related decrease in feed consumption of the P1 females in the 75 ppm exposure group when compared to controls, and these differences reached statistical significance for most measurement intervals. Feed consumption of the 75 ppm females was also decreased throughout gestation (≤ 12%) when compared to controls. During lactation, feed consumption of the 75 ppm females was slightly decreased when compared to controls, although these differences only reached statistical significance for three measurement intervals (LD 14-17, 17-19, and 23-26). There were no treatment-related or statistical differences in feed consumption of P1 males and females exposed to 25 or 5 ppm methyl acrylate when compared to controls.

Selected P1 Male Feed Consumption Data
Mean g/Animal/Day
ppm: 0 5 25 75
TD 1-7 22.4 21.7 22.8 20.0*
TD 7-14 24.2 24.8 24.7 23.0*
TD 21-28 24.9 24.1 25.9 24.8
TD 42-49 26.8 26.1 26.1 25.7
TD 56-63 27.4 26.0 26.6 25.0*
TD 86-91 27.1 25.8 27.4 25.5
* Statistically different from control mean by Dunnett’s test, alpha = 0.05.

Selected P1 Female Feed Consumption Data
Mean g/Animal/Day
ppm: 0 5 25 75
Premating days 1-7 16.2 15.0 15.9 14.2$
Premating days 7-14 16.6 16.9 16.6 15.4*
Premating days 21-28 17.6 17.3 17.7 16.7
Premating days 42-49 18.8 18.0 17.8 17.3*
Premating days 56-63 18.0 17.2 17.2 13.3$
Premating days 63-70 18.1 17.4 17.3 18.8
GD 0-7 22.6 21.3 22.1 19.9*
GD 7-14 23.8 22.9 23.8 21.7*
GD 14-21 23.2 23.1 22.6 21.0*
LD 1-4 29.4 32.1 29.8 30.4
LD 7-11 40.6 41.8 41.2 38.1
LD 14-17 51.8 52.1 50.6 48.3$
LD 23-26 90.9 90.9 92.5 87.3$
* Statistically different from control mean by Dunnett’s test, alpha = 0.05.
$ Statistically different from control mean by Wilcoxon’s test, alpha = 0.05.

There was a treatment-related decrease in feed consumption of the P2 males in the 75 ppm exposure group when compared to controls, and these differences reached statistical significance for the majority of measurement intervals throughout the second generation. During the 10-week premating period, there was a treatment-related decrease in feed consumption of the P2 females in the 75 ppm exposure group when compared to controls, and these differences also reached statistical significance for most measurement intervals. Feed consumption of the 75 ppm females was also decreased throughout gestation (≤ 10%) when compared to controls. During lactation, feed consumption of the 75 ppm females was slightly decreased when compared to controls, although these differences only reached statistical significance for two measurement intervals (LD 7-11 and 14-17). There were no treatment-related differences in feed consumption of P2 males and females exposed to 25 or 5 ppm methyl acrylate when compared to controls. The difference in feed consumption of 5 ppm males when compared to controls was statistically identified and decreased for two measurement intervals (TD 1-6 and 34-41), however, this was not considered to be a treatment-related effect due to the lack of both a dose-response relationship and temporal association.

Selected P2 Male Feed Consumption Data
Mean g/Animal/Day
ppm: 0 5 25 75
TD 1-6 24.3 22.6* 24.7 20.8*
TD 6-13 27.0 25.6 27.2 23.8*
TD 20-27 28.7 27.6 29.4 26.2*
TD 34-41 29.4 27.6* 29.5 26.9*
TD 41-48 28.7 27.6 29.9 27.0
TD 55-62 29.3 28.0 29.7 27.1*
TD 90-97 29.0 28.5 29.2 26.6*
* Statistically different from control mean by Dunnett’s test, alpha = 0.05.

Selected P2 Female Feed Consumption Data
Mean g/Animal/Day
ppm: 0 5 25 75
Premating days 1-6 19.3 19.0 18.4 17.1$
Premating days 6-13 19.9 19.6 19.2 17.7*
Premating days 20-27 20.2 19.4 19.8 18.0*
Premating days 41-48 20.4 19.1 20.0 19.2
Premating days 55-62 18.6 19.1 18.9 18.8
Premating days 62-69 19.1 18.3 18.8 17.6*
GD 0-7 23.1 22.3 22.7 21.1*
GD 7-14 25.2 23.9 25.0 22.7*
GD 14-21 24.1 23.0 23.1 21.9*
LD 1-4 33.7 32.4 30.6 33.0
LD 7-11 46.0 44.7 43.7 41.9*
LD 14-17 55.3 53.7 53.0 51.1*
LD 23-26 95.0 93.2 92.5 91.9
* Statistically different from control mean by Dunnett’s test, alpha = 0.05.
$ Statistically different from control mean by Wilcoxon’s test, alpha = 0.05.


Body Weights/Body Weight Gains
There was a treatment-related decrease in the body weight of P1 males of the 75 ppm exposure group when compared to controls, although these differences only reached statistical significance on TD 7 and 14 throughout the entire first generation. Similarly, there was a treatment-related decrease in the body weight of P1 females of the 75 ppm exposure group, which reached statistical significance on three days (TD 21, 63, and 70) of the 10-week premating period. There was a treatment-related decrease in the body weight of P1 females of the 75 ppm exposure group across the entire
gestation and lactation period. However, gestation body weight gain of the 75 ppm females remained comparable to controls. During lactation, the 75 ppm females did not lose as much body weight as controls, which could have been related to their lower body weight at the start of lactation. There were no treatment-related differences in body weight of P1 males and body weight/body weight gain of P1 females exposed to 25 or 5 ppm methyl acrylate when compared to controls. The difference in body weight of 5 ppm males (TD 7) and gestation body weight gain of 5 ppm females (GD 0-7) was statistically identified and decreased when compared to their respective controls. However, this was not considered to be a treatmentrelated effect due to the lack of a dose-response relationship and the low incidence.

Selected P1 Male Body Weights
Mean Body Weight (g)
ppm 0 5 25 75
TD 1 193.9 190.4 193.6 191.9
TD 7 237.8 228.0* 235.9 226.3*
TD 14 291.1 286.8 284.9 276.7*
TD 28 369.3 358.5 366.7 358.6
TD 70 512.4 492.5 499.2 487.3
* Statistically different from control mean by Dunnett’s test, alpha = 0.05.

Selected P1 Female Pre-Breeding Body Weights
Mean Body Weight (g)
ppm 0 5 25 75
TD 1 139.4 136.4 138.9 139.8
TD 7 158.7 153.8 159.0 152.5
TD 21 203.8 203.0 204.6 191.5*
TD 63 273.1 266.1 272.4 248.1*
TD 70 281.7 272.0 276.6 258.5*
* Statistically different from control mean by Dunnett’s test, alpha = 0.05

Selected P1 Gestation/Lactation Body Weights/Body Weight Gains
Gestation Mean Body Weight (g)
ppm 0 5 25 75
GD 0 287.4 280.1 284.3 261.8*
GD 7 319.3 302.7 315.8 289.0*
GD 14 350.1 337.2 347.5 318.5*
GD 21 433.8 429.4 435.9 404.6*

Gestation Mean Body Weight Gains (g)
GD 0-21 146.4 149.3 151.6 142.9
Lactation Mean Body Weight (g)
LD 1 330.9 316.4 321.6 297.7*
LD 4 343.8 335.6 337.2 312.6*
LD 7 328.0 323.0 324.4 297.9*
LD 14 336.9 334.8 335.6 308.8*
LD 28 313.4 306.6 309.3 294.6*
Lactation Mean Body Weight Gains (g)
LD 1-28 -17.5 -9.8 -12.3 -3.1*
* Statistically different from control mean by Dunnett’s test, alpha = 0.05.

There was a treatment-related decrease in the body weight of P2 males of the 75 ppm exposure group when compared to controls, which was statistically identified throughout the entire second generation. Similarly, there was a treatment-related decrease in the body weight of P2 females of the 75 ppm exposure group, which reached statistical significance on all measurement days during the 10-week premating period. There was a treatment-related decrease in the body weight of P2 females of the 75 ppm exposure group across the entire gestation and lactation periods. The gestation body weight gains of the 75 ppm females were significantly lower than control values, however, this difference was equivocal when all dose groups were considered. As in the P1 females, the net body weight loss typical of lactating female rats was less in the 75 ppm females than it was in controls. There were no treatment-related differences in body weight of P2 males and body weight/body weight gain of P2 females exposed to 25 or 5 ppm methyl acrylate when compared to controls. Statistical differences in the body weight/body weight gain of 25 or 5 ppm females were not considered to be treatment-related due to the lack of a doseresponse relationship and/or the low incidence.

Selected P2 Male Body Weights
Mean Body Weight (g)
ppm 0 5 25 75
TD 1 169.7 158.0 170.9 148.4*
TD 6 212.6 200.7 213.6 181.2*
TD 13 274.6 258.9 277.9 239.6*
TD 27 373.7 365.2 379.0 330.4*
TD 69 538.4 512.4 540.3 472.3*
* Statistically different from control mean by Dunnett’s test, alpha = 0.05.

Selected P2 Female Pre-Breeding Body Weights
Mean Body Weight (g)
ppm 0 5 25 75
TD 1 143.6 135.6 135.6 125.1*
TD 6 166.4 160.0 156.4 144.3*
TD 13 194.3 187.0 183.1 169.9*
TD 27 238.9 229.4 228.3 206.4*
TD 69 299.5 288.1 293.2 264.1*
* Statistically different from control mean by Dunnett’s test, alpha = 0.05
Selected P2 Gestation/Lactation Body Weights/Body Weight Gains
Gestation Mean Body Weight (g)
ppm 0 5 25 75
GD 0 298.7 292.5 290.2 266.5*
GD 7 334.0 319.7 321.7 294.7*
GD 14 367.1 350.4 353.3 324.4*
GD 21 459.3 437.6 440.5 412.4*
Gestation Mean Body Weight Gains (g)
GD 0-21 160.6 145.1* 150.3 145.9*
Lactation Mean Body Weight (g)
LD 1 345.1 328.3 337.0 303.8*
LD 4 365.4 345.6* 350.4 323.0*
LD 7 352.6 333.7 336.4 311.2*
LD 14 358.3 338.3* 341.1 321.2*
LD 28 322.5 310.0 314.4 298.0*
Lactation Mean Body Weight Gains (g)
LD 1-28 -22.6 -18.2 -22.5 -6.1*
* Statistically different from control mean by Dunnett’s test, alpha = 0.05.

Organ Weights
P1 males and females exposed to 75 ppm had treatment-related lower final body weights (statistically identified in females at 75 ppm). The final body
weights of P1 males and females exposed to 75 ppm were 5.0% and 7.7% lower than controls, respectively. The relative weights of the testes and epididymides of males exposed to 75 ppm, and the relative weights of the liver and brain of females exposed to 75 ppm were statistically identified as higher than controls. The elevated relative organ weights of males and females exposed to 75 ppm were interpreted to be reflective of the lower body weights of these animals as the absolute weights of the organs were not different from the controls. The relative testes weight of males exposed to 5 ppm, and the relative liver weight of females exposed to 5 ppm were statistically identified as higher than controls. These organ weight alterations were interpreted to be unrelated to treatment due to the lack of a dose response. The absolute pituitary weights of males exposed to 5 or 25 ppm, and females exposed to 5, 25, or 75 ppm were statistically identified as lower than controls. In addition, the relative pituitary weight of males exposed to 25 ppm was statistically identified as lower than controls. The alterations in pituitary weights were interpreted to be unrelated to treatment because of the a lack of a clear dose response, the absence of any histopathologic correlates in males and females from the high-dose group, and because all of the pituitary weights were within historical controls ranges of studies recently conducted at this laboratory.

Organ Weight Data – P1 Adults
Concentration (ppm)
0 Historical1 5 25 75
Parameter MALES
Final Body Weight (g) 554.0 520.1-581.8 540.9 549.8 526.1a
Relative Testes (g/100g bw) 0.635 0.608-0.695 0.698* 0.673 0.709*
Relative Epididymides (g/100g bw) 0.248 0.238-0.277 0.264 0.261 0.277*
Absolute Pituitary (g) 0.0146 0.011-0.015 0.0133* 0.0130* 0.0138
Relative Pituitary (g/100g bw) 0.0026 0.002-0.002 0.0025 0.0024* 0.0026
Parameter FEMALES
Final Body Weight (g) 314.2 278.0-330.4 300.8 311.5 290.1*a
Relative Liver (g/100g bw) 2.878 2.994-3.491 3.103* 3.008 3.105*
Relative Brain (g/100g bw) 0.658 0.651-0.692 0.685 0.658 0.699$
Absolute Pituitary (g) 0.0200 0.012-0.018 0.0175* 0.0179* 0.0171*
*Statistically different from control mean by Dunnett’s Test, alpha = 0.05.
$Statistically different from control mean by Wilcoxon’s Test, alpha =0.05.
1Historical controls group mean range from seven dietary studies reported between 2002 and 2006.
a- Values interpreted to be treatment-related effects.

P2 males and females exposed to 75 ppm had statistically identified treatment-related lower final body weights. The final body weights of P2 males and females exposed to 75 ppm were 13.1% and 9.6% lower than controls, respectively. The relative weights of the brain, testes, seminal vesicles (with coagulating glands) and epididymides of males exposed to 75 ppm, and the relative weights of the adrenals and brain of females exposed to 75 ppm were statistically identified as higher than controls. The absolute weights of the adrenals, kidneys, spleen, pituitary gland, and thyroid gland of males exposed to 75 ppm, and the absolute weights of the kidneys, spleen and thyroid gland of females exposed to 75 ppm were statistically identified as lower than controls. The organ weight alterations of males and females exposed to 75 ppm were interpreted to be reflective of the lower body weights of these animals. Males exposed to 25 ppm had statistically identified lower absolute and relative pituitary weights, and females exposed to 25 ppm had a statistically identified lower absolute thyroid weight. Males exposed to 5 ppm had a statistically identified higher relative testes weight, and females exposed to 5 ppm had statistically identified higher absolute and relative adrenal weights. The organ weight alterations from the 5 and 25 ppm dose groups were interpreted to be unrelated to treatment due to the lack of a clear dose response and/or the values were within historical controls
ranges of studies recently conducted at this laboratory.

Organ Weight Data – P2 Adults
Concentration (ppm)
0 Historical1 5 25 75
Parameter MALES
Final Body Weight (g) 624.4 606.9-674.8 599.9 627.6 542.9*a
Absolute Adrenal Glands (g) 0.055 0.062-0.073 0.054 0.056 0.048*
Absolute Kidneys (g) 4.058 3.924-4.350 4.010 4.002 3.671*
Relative Brain (g/100g bw 0.346 0.333-0.386 0.363 0.344 0.386*
Absolute Spleen (g) 0.895 0.845-0.963 0.905 0.867 0.783*
Relative Testes (g/100g bw) 0.582 0.571-0.641 0.636* 0.593 0.662*
Relative Seminal Vesicle (g/100g bw) 0.319 0.266-0.319 0.322 0.312 0.367*
Relative Epididymides (g/100g bw) 0.223 0.224-0.248 0.238 0.229 0.255*
Absolute Pituitary (g) 0.0149 0.009-0.017 0.0141 0.0137* 0.0134*
Relative Pituitary (g/100g bw) 0.0024 0.002-0.003 0.0024 0.0022* 0.0025
Absolute Thyroid Gland (g) 0.0253 0.0224-0.0284 0.0255 0.0269 0.0224*
Parameter FEMALES
Final Body Weight (g) 326.3 296.3-347.2 313.7 318.4 295.0*a
Absolute Adrenal Glands (g) 0.062 0.070-0.111 0.068* 0.064 0.067
Relative Adrenal Glands (g/100g bw) 0.019 0.023-0.035 0.022* 0.020 0.023*
Absolute Kidneys (g) 2.274 2.187-2.424 2.259 2.149 2.108*
Relative Brain (g/100g bw) 0.620 0.588-0.703 0.644 0.628 0.669*
Absolute Spleen (g) 0.585 0.593-0.620 0.543 0.562 0.513*
Absolute Thyroid Gland (g) 0.0203 0.0166-0.0202 0.0182 0.0180* 0.0180*
*Statistically different from control mean by Dunnett’s Test, alpha = 0.05.
1Historical controls group mean range from seven dietary studies reported between 2002 and 2006.
a-Values interpreted to be treatment-related effects.
Gross Pathology
There were no treatment-related gross pathologic observations. All gross pathologic observations were considered to be incidental findings, unassociated with exposure to methyl acrylate.

Histopathology
Treatment-related histopathologic effects were present in the nasal tissues of P1 and P2 males and females given 25 or 75 ppm. The incidence and severity of the nasal effects were dose-related. Degeneration with regeneration of the olfactory epithelium (very slight to moderate) occurred in all P1 and P2 males and females exposed to 75 ppm. The degeneration consisted of thinning and disarray of the olfactory epithelial cells, which was most prevalent in the anterior and dorsal aspects of the nasal passages. Regenerative hyperplasia of the olfactory epithelium accompanied the degenerative change in multifocal sites. A lesser degree of multifocal olfactory epithelial degeneration (very slight), without accompanying regenerative hyperplasia, was noted in 7/27 P1 females exposed to 25 ppm, and in 6/27 P2 males and 8/27 P2 females exposed to 25 ppm. One P1 female and one P2 female exposed to 5 ppm also had very slight multifocal olfactory epithelial degeneration. However, the degeneration was located in only two sites of the nose for both of these animals, and therefore was interpreted to be comparable with spontaneous focal olfactory epithelial degeneration that was noted in 2/27 control group P1 females and 3/27 control group P2 females, and not an effect of treatment.

There were several histopathologic effects that accompanied the degeneration of the olfactory epithelium. Very slight or slight degeneration of the olfactory nerve was present in most of the P1 and P2 males and females exposed to 75 ppm, and one P1 male exposed to 25 ppm. This effect was characterized by thinning of the axons and reduction in the diameter of the olfactory nerve fascicles in areas of olfactory epithelial degeneration. Very slight or slight multifocal chronic-active inflammation accompanied the olfactory epithelial degeneration in 16/27 P1 males, 20/27 P1 females, 14/27 P2 males, and 8/27 P2 females exposed to 75 ppm, and in one or two males and females from both generations exposed to 25 ppm. The inflammation
consisted of neutrophils in the olfactory epithelium, with or without the presence of a mucopurulent exudate. Very slight multifocal necrosis of individual olfactory epithelial cells, with or without exfoliation of necrotic cells into the lumen of the nasal passages, was present in most of the P1 and P2 males and females exposed to 75 ppm, and a few P1 and P2 animals (one to four per sex) exposed to 25 ppm. One P1 female exposed to 5 ppm also had very slight multifocal necrosis of individual olfactory epithelial cells. However, the necrosis was located in only two sites of the nose in this animal, and therefore was interpreted to be comparable with spontaneous focal olfactory epithelial cell necrosis that was noted in one control group P1 male, one control group P1 female, and one control group P2 female, and not an effect of treatment.

A treatment-related increase in the incidence of very slight or slight multifocal hyperplasia of the transitional epithelium that covers the nasal turbinates was present in P1 and P2 males and females exposed to 25 or 75 ppm. The incidence and severity of transitional epithelial hyperplasia in P1 and P2 males and females exposed to 5 ppm was comparable to controls.

A treatment-related increase in the incidence of very slight or slight diffuse hyperplasia and hypertrophy of the respiratory epithelium that covers the nasal septum and dorsal portion of the anterior nasal cavity was present in P1 males and females exposed to 25 or 75 ppm, and in P2 males and females exposed to 75 ppm. The incidence and severity of respiratory epithelial hyperplasia and hypertrophy in P1 and P2 males and females exposed to 5 ppm was comparable to controls.

Treatment-related very slight focal or multifocal mineralization of the olfactory epithelium was present in one or two P1 and P2 animals exposed to 25 ppm, 6/27 P1 males, 4/27 P1 females, 16/27 P2 males and 14/27 P2 females exposed to 75 ppm. The mineralization was present in areas olfactory epithelial degeneration. One P1 female exposed to 75 ppm also had slight multifocal mineralization of the nasal respiratory epithelium that was interpreted to be treatment related. Other treatmentrelated nasal effects consisted of very slight multifocal squamous metaplasia of the transitional epithelium in 5/27 P1 males exposed to 75 ppm, and ulceration of the olfactory epithelium in four P1 males, one P1 female, and one P2 female exposed to
75 ppm.

All other histopathologic observations were considered to be spontaneous alterations, or caused by accidental trauma, unassociated with inhalation exposure of methyl acrylate. There were no histopathologic systemic effects in P1 or P2 rats at any exposure level. The NOEC for histopathologic nasal effects was 5 ppm.

Histopathologic Nasal Tissue Effects – P1 Males
Dose (ppm) 0 5 25 75
NASAL TISSUE - PHARYNX (number examined) (27) (27) (27) (27)
Degeneration, olfactory nerve, multifocal -very slight 0 0 1a 11a
-slight 0 0 0 14a
Degeneration with Regeneration, olfactory epithelium, multifocal
-slight 0 0 1a 12a
-moderate 0 0 0 15a
Hyperplasia, transitional epithelium; multifocal -very slight 3 4 17a 12a
-slight 0 0 0 15a
Hyperplasia and Hypertrophy, goblet cell, respiratory epithelium, diffuse
-very slight 1 0 4a 1
-slight 0 0 1a 22a
Inflammation, chronic active, olfactory epithelium, multifocal
-very slight 1 0 2 15a
-slight 0 0 0 1a
Metaplasia, squamous, transitional epithelium, multifocal -very slight 0 0 0 5a
Mineralization, olfactory epithelium, focal -very slight 0 0 0 1a
Mineralization, olfactory epithelium, multifocal -very slight 0 0 1a 5a
Necrosis, individual cell, olfactory epithelium, focal -very slight 1 0 1 0
Necrosis, individual cell, olfactory epithelium, multifocal -very slight 0 0 1a 26a
Ulcer, olfactory epithelium, focal -very slight 0 0 0 4a
a- Indicates the effects judged to be treatment-related.

Results Continued in Remarks Section (below)

Effect levels (P0)

1

Dose descriptor:

NOEC

Remarks:

maternal toxicity

Effect level:

ca. 0.092 mg/L air (analytical)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: corresponding to 25 ppm; based on decreases in pup weight at 75 ppm which were secondary to parental toxicity.

Remarks on result:

other: Generation: P1, P2 (migrated information)

2

Dose descriptor:

NOEC

Remarks:

reproductive toxicity

Effect level:

ca. 0.269 mg/L air (analytical)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: corresponding to 75 ppm; the highest concentration tested.

Remarks on result:

other: Generation: P1 and P2 (migrated information)

3

Dose descriptor:

NOEC

Remarks:

developmental toxicity

Effect level:

ca. 0.092 mg/L air (analytical)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: based on decreased body weight of the pups

Remarks on result:

other: Generation: P3 (migrated information)

4

Dose descriptor:

NOEC

Remarks:

maternal local toxicity

Effect level:

ca. 0.019 mg/L air (analytical)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: corresponding to 5 ppm; based on histologic changes in nasal tissues.

Remarks on result:

other: Generation: P1 and P2 (migrated information)

Results: F1 generation

Details on results (F1)

In-Life Observations

No treatment-related effects on behavior or demeanor were observed in any phase of the study at any dose level. A number of incidental observations bearing no relation to treatment were observed.

Observations made on F1 and F2 pups during their respective lactation periods revealed no effects related to treatment. Incidental findings, which included a small number of observations in the control, low-, middle-, and high-dose groups, were seen with no evidence of a dose-response relationship. Included among these incidental findings was a single high dose pup which exhibited a head tilt and circling behavior associated with overgrown incisors. This pup was euthanized on lactation day 25.

Reproductive Indices, Pup Survival and Sex Ratio
There were no effects of treatment at any exposure level on mating, conception, fertility or gestation indices, post-implantation loss, time to mating, gestation length, pup survival or pup sex ratio in either generation.

Litter Size
There were no effects of treatment on the number of pups born live, number of pups born dead, or on litter size at any time interval in any exposure group for either generation.

Pup Body Weight
F1 pup body weights from all exposure groups were comparable to control until PND 14. Male and female pups from the 75 ppm exposure group had decreased body weights that were statistically identified when compared to control on PNDs 14, 21, and 28. There were no treatment-related findings for F1 pup body weights from the 25 or 5 ppm exposure groups when compared to control. On PND 7, there was a statistically identified decrease in pup body weights of F1 females from the 5 ppm exposure group. This was considered spurious and unrelated to treatment due to the lack of a dose response relationship and because it was not repeated in the next generation.

Treatment-related effects on the body weights of F2 pups were similar to what was seen in the previous generation. F2 pup body weights from all exposure groups were comparable to control until PND 14. Male and female pups from the 75 ppm exposure group had decreased body weights that were statistically identified when compared to control on PNDs 14, 21, and 28. There were no treatment-related or statistical findings for F1 pup body weights from the 25 or 5 ppm exposure groups when compared to control.

These findings are likely secondary to maternal toxicity in the form of decreased maternal body weights of ~10% and severe nasal irritation. This conclusion is supported by a feed restriction study where a 10-20% decrease in maternal body weight can lead to decreased pup weights by as much as 21% (Carney, et al., 2004).

Selected F1 Pup Body Weights (g)
0 ppm 5 ppm 25 ppm 75 ppm
PND 14 Males 27.0 26.7 26.3 24.3*
Percent from Control NA -1% -3% -10%
PND 14 Females 26.5 25.8 25.6 23.7*
Percent from Control NA -3% -3% -11%
PND 21 Males 44.2 42.3 42.6 39.5*
Percent from Control NA -4% -4% -11%
PND 21 Females 43.8 41.1 41.4 39.3*
Percent from Control NA -6% -6% -10%
PND 28 Males 83.1 82.2 82.0 77.3*
Percent from Control NA -1% -1% -7%
PND 28 Females 79.4 76.6 76.6 73.1*
Percent from Control NA -4% -4% -8%
*Statistically different from control mean by Dunnett’s Test, alpha = 0.05.

Selected F2 Pup Body Weights (g)
0 ppm 5 ppm 25 ppm 75 ppm
PND 14 Males 30.3 29.8 29.6 27.4*
Percent from Control NA -2% -2% -10%
PND 14 Females 29.7 28.7 29.0 26.7*
Percent from Control NA -3% -2% -10%
PND 21 Males 49.0 48.7 47.5 44.1*
Percent from Control NA -1% -3% -10%
PND 21 Females 48.3 46.5 46.8 42.9*
Percent from Control NA -4% -3% -11%
PND 28 Males 89.7 89.7 87.5 83.4*
Percent from Control NA 0% -2% -7%
PND 28 Females 84.2 82.3 82.0 77.8*
Percent from Control NA -2% -3% -8%
*Statistically different from control mean by Dunnett’s Test, alpha = 0.05.

Puberty Onset
Age at vaginal opening and age at preputial separation were similar in all exposure groups, indicating no effect of treatment on these end points despite the lower body weight of the 75 ppm animals.

Organ Weights
The final body weights of F1 weanling males and females from the 75 ppm group were approximately 6% lower than controls, and although not statistically identified, were considered treatment-related due to the immediately preceding decrease in pup body weights from PND 14-28. There were no
treatment-related alterations in organ weights of F1 weanlings at any dose level.

Final Body Weight Data – F1 Weanlings
Concentration (ppm)
0 5 25 75
Parameter MALES
Final Body Weight (g) 88.1 86.7 87.2 82.6a
Parameter FEMALES
Final Body Weight (g) 81.9 77.8 80.6 76.7a
a- Values interpreted to be treatment-related effects.

F2 weanling males and females from the 75 ppm group had treatment-related lower final body weights (statistically identified in females at 75 ppm). The final body weights of F2 weanling males and females from the 75 ppm group were 5.8% and 7.7% lower than controls, respectively. As in the 75 ppm group F1 pups, these decreases in final body weights (PND 29) were reflective of the statistically significant decreases in pup body weights during the preceding two weeks. There were no treatment-related alterations in organ weights of F2 weanlings at any dose level. The only statistically identified organ weight alteration was a higher absolute brain weight in F2 male weanlings from the 5 ppm exposure group, which was unrelated to treatment due to the lack of a dose response.

Final Body Weight Data – F2 Weanlings
Concentration (ppm)
0 5 25 75
Parameter MALES
Final Body Weight (g) 94.6 93.0 94.6 89.1a
Parameter FEMALES
Final Body Weight (g) 87.2 84.7 84.5 80.4*a
*Statistically different from control mean by Dunnett’s Test, alpha = 0.05.
a- Values interpreted to be treatment-related effects.

Gross Pathology
There were no treatment-related gross pathologic observations in F1 weanlings at any exposure level. In F2 weanlings, 2/81 males and 3/78 females from the 75 ppm exposure group had necrosis of the tail. This observation may have been related to treatment, but the significance of the tail necrosis is not known. All other gross pathologic observations from F1 and F2 weanlings were considered to be spontaneous alterations, unassociated with exposure to methyl acrylate.

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Results- Continued

Histopathologic Nasal Tissue Effects

P1 Females

Dose (ppm) 0 5 25 75

NASAL TISSUE - PHARYNX (number examined) (27) (27) (27) (27)

Degeneration, olfactory epithelium, focal -very slight 2 1 4 0

Degeneration, olfactory epithelium, multifocal -very slight 0 1 7a 0

Degeneration, olfactory nerve, multifocal -very slight 0 0 0 8a

-slight 0 0 0 19a

Degeneration with Regeneration, olfactory epithelium, multifocal-slight 0 0 0 8a

-moderate 0 0 0 19a

Hyperplasia, transitional epithelium; multifocal -very slight 2 1 23a 24a

-slight 0 0 2a 3a

Hyperplasia and Hypertrophy, goblet cell, respiratory epithelium, diffuse-very slight 0 1 8a 10a

-slight 0 0 13a 1a

Inflammation, chronic active, olfactory epithelium, multifocal-very slight 0 0 1 20a

Inflammation, chronic active, respiratory epithelium, multifocal-very slight 0 0 1 5a

Mineralization, olfactory epithelium, focal -very slight 0 0 0 2a

Mineralization, olfactory epithelium, multifocal -very slight 0 0 0 2a

Mineralization, respiratory epithelium, focal -slight 0 0 0 1a

Necrosis, individual cell, olfactory epithelium, focal -very slight 1 0 3 0

Necrosis, individual cell, olfactory epithelium, multifocal -very slight 0 1 2a 26a

Ulcer, olfactory epithelium, focal -very slight 0 0 0 1a

a-Indicates the effects judged to be treatment-related.  

Histopathologic Nasal Tissue Effects

P2 Males Dose (ppm) 0 5 25 75

NASAL TISSUE - PHARYNX (number examined) (27) (27) (27) (27)

Degeneration, olfactory epithelium, focal -very slight 0 0 1 0

Degeneration, olfactory epithelium, multifocal, -very slight 0 0 6a 0

Degeneration, olfactory nerve, multifocal -very slight 0 0 0 14a

-slight 0 0 0 13a

Degeneration with Regeneration, olfactory epithelium, multifocal-slight 0 0 0 13a

-moderate 0 0 0 14a

Hyperplasia, transitional epithelium; multifocal -very slight 4 4 18a 8a

-slight 0 0 2a 19a

Hyperplasia and Hypertrophy, goblet cell, respiratory epithelium, diffuse-very slight 0 0 0 6a

-slight 0 0 0 3a

Inflammation, chronic active, olfactory epithelium, multifocal-very slight 0 0 0 14a

Mineralization, olfactory epithelium, focal -very slight 0 0 1a 1a

Mineralization, olfactory epithelium, multifocal -very slight 0 0 1a 15a

Necrosis, individual cell, olfactory epithelium, multifocal -very slight 0 0 1a 24a

Ulcer, olfactory epithelium, focal -very slight 1 0 0 1a a-Indicates the effects judged to be treatment-related.

Histopathologic Nasal Tissue Effects

P2 Females Dose (ppm) 0 5 25 75

NASAL TISSUE - PHARYNX (number examined) (27) (27) (27) (27)

Degeneration, olfactory epithelium, focal -very slight 3 2 4 0

Degeneration, olfactory epithelium, multifocal -very slight 0 1 8a 0

Degeneration, olfactory nerve, multifocal -very slight 0 0 0 14a

-slight 0 0 0 12a

Degeneration with Regeneration, olfactory epithelium, multifocal-very slight 0 0 0 1a

-slight 0 0 0 14a

-moderate 0 0 0 12a

Hyperplasia, transitional epithelium; multifocal -very slight 9 6 23a 25a

-slight 1 0 0 1a

Hyperplasia and Hypertrophy, goblet cell, respiratory epithelium, diffuse-very slight 7 8 11 16a

-slight 3 1 5 2

Inflammation, chronic active, olfactory epithelium, multifocal-very slight 0 0 1a 8a

Mineralization, olfactory epithelium, multifocal -very slight 0 0 1a 14a

Necrosis, individual cell, olfactory epithelium, focal -very slight 1 0 1 0

Necrosis, individual cell, olfactory epithelium, multifocal -very slight 0 0 4a 27a

a-Indicates the effects judged to be treatment-related.

One P1 male exposed to 75 ppm (animal number 08A1350) died on test day 70. The cause of death was not determined. One P1 male exposed to 75 ppm (animal umber 08A1351) was euthanized moribund on test day 106. The cause of moribundity was urolithiasis, with associated inflammation and transitional cell hyperplasia of the urinary bladder and kidneys. One P1 male from the control group (animal number 08A1269) was euthanized moribund on test day 98. The cause of moribundity was lymphoid cell leukemia. Another P1 male from the control (animal number 08A1250) was euthanized on test day 113 due to accidental fracture of the upper jaw. One P2 female exposed to 25 ppm (animal number 08A5190) was euthanized on test day 57 due to severe inflammation of the hind feet. One P2 male exposed to 5 ppm (animal number 08A5040) was euthanized moribund on test day 87. The cause of moribundity was severe inflammation of the periodontal tissue associated with fracture of the upper incisors. One P2 female from the control group (animal number 08A5134) was euthanized on test day 70 due to accidental fracture of the nose. Histologic examination of the reproductive organs of animals with signs of reduced fertility did not reveal any effects of treatment. There were no treatment-related or statistically-identified differences in the mean number of small and growing ovarian follicles in females exposed to 75 ppm as compared to females from the control group.  

Sperm Parameters

There were no treatment-related effects of methyl acrylate on any sperm analysis parameter at any exposure level in either generation. There was a statistically identified increase in epididymal and testicular sperm counts of P1 males of the 75 ppm exposure group when compared to controls, which was due to two males in the control group (1258 and 1263) with very low sperm counts.  

Estrous Cyclicity

There was no evidence of an effect on estrous cyclicity at any dose level of methyl acrylate in either generation.