Ammonium 7-(2,6-dimethyl-8-(2,2-dimethylbutyryloxy)-1,2,6,7,8,8a-hexahydro-1-naphthyl)-3,5-dihydroxyheptanoate

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25th August 1986 to 19th January 1987

Reliability:

2 (reliable with restrictions)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Principles of method if other than guideline:

- Principle of test: To evaluate the effects of MK-0733 administered to F0 female rats during late gestation and lactation
- Parameters analysed / observed:growth, developmental behaviour, reproductive performance and fertility of offspring of treated F0 females

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Ammonium 7-(2,6-dimethyl-8-(2,2-dimethylbutyryloxy)-1,2,6,7,8,8a-hexahydro-1-naphthyl)-3,5-dihydroxyheptanoate

EC Number:

404-520-2

EC Name:

Ammonium 7-(2,6-dimethyl-8-(2,2-dimethylbutyryloxy)-1,2,6,7,8,8a-hexahydro-1-naphthyl)-3,5-dihydroxyheptanoate

Cas Number:

139893-43-9

Molecular formula:

C25 H43 O6 N

IUPAC Name:

ammonium 7-{8-[(2,2-dimethylbutanoyl)oxy]-2,6-dimethyl-1,2,6,7,8,8a-hexahydronaphthalen-1-yl}-3,5-dihydroxyheptanoate

Test material form:

solid: particulate/powder

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on species / strain selection:

CRL:CD(SD)BR

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Wilmington, MA
- Age at study initiation: 12wks
- Weight at study initiation: 212- 280g
- Housing: Singly housed in metal cages up to Day 17 of gestation, thereafter plastic boxes for delivery
- Diet: Purina Pet Chow #5002 ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 27
- Humidity (%): >50%

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: 0.5% Aqueous Methylcellulose

Duration of treatment / exposure:

Day 15 of gestation to Day 21 post-partum

Frequency of treatment:

Once in the morning and once in the afternoon with an interval of at least 4 hours but less than 6 hours between doses

Details on study schedule:

5 months duration

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

3.125 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

6.25 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

12.5 mg/kg bw/day (nominal)

No. of animals per sex per dose:

20

Control animals:

yes

Details on study design:

Mating Procedure:
The females were placed with untreated males of the same strain, 1 female with 1 male, The mating period was limited to 16 nights after which the females were removed from the cages of the males. Mating was confirmed by presence of sperm in the daily vaginal lavage. The day sperm was found was considered to be Day 0 of gestation.

The test article was mixed in vehicle just prior to dosing. The volume administered was 5ml/kg b.i.d. Doses were administered twice daily, from Day 15 of gestation to Day 21 postpartum with an interval of 4-6 hours.

At Postnatal week 13, an F1 male and F1 female from each litter were mated. Upon detection of spermatazoa in the vaginal lavage, the mated females were removed.

Positive control:

no

Examinations

Parental animals: Observations and examinations:

F0 females were examined daily for clinical signs from Day 15 of gestation until sacrifice at weaning of F1 pups. Body weights were recorded on Days 0, 15, 17, 19 and 20 and daily until parturition. F0 females were weighed postpartum Days 0, 7, 14 and 21. Females who did not mate were weighed on Day 0, 7, 14, 21 and 24. Food consumption was monitored.

In order to evaluate reproductive performance and status, the following were recorded:
Incidence of matings, time to mating, implants per female, post-implantation survival, parturition behaviour, date and time of delivery, incidence of pregnancy, number of F0 female with live pups and number of live pups.

At weaning of F1 pups, F0 females were sacrificed and gross necroscopy was carried out.

Litter observations:

F1 pups:
Day 0 - pups were weighed, counted, externally examined and sexed. Pups were observed for clinical signs daily until weaning and twice weekly until sacrifice. Body weights were recorded postnatal days 7, 14 and 21 and sex confirmed.

Developmental Tests:
Two males and two females were randomly selected and tested for auditory startle response on Postnatal Days12 and 16 and for free fall righting reflex Postnatal Days 14 and 18.

On day 21/22 post partum, 2 males and 2 females were weaned and randomly selected for continuation. The following tests were carried out:
Developmental signs & behaviour
Testes descent
Vaginal canalisation
Activity in open field
Swimming maze,
Opthalmologic examination

Females were weighed Day 0 and 20 of gestation and Day 0 Post-partum. were recorded on Days 0, 15, 17, 19 and 20 and daily until parturition. F1 females were weighed postpartum Days 0, 7, 14 and 21. Females who did not mate were weighed on Day 0, 7, 14, 21 and 24.

Pregnant F1 females had parturition data recorded: Parturition behaviour, date and time, no. of metrial glands and reproductive status.

F2 pups were weighed, counted, externally examined and sexed. Within one week of birth all F2 pups were killed and discarded.

Postmortem examinations (parental animals):

At weaning of F1 pups, F0 females were sacrificed and gross necroscopy was carried out.

Postmortem examinations (offspring):

Non-pregnant F1 females and males were sacrificed and gross examination of the epididymides and testes carried out on the males.

F1 females were sacrificed 0-3 days post-partum and a gross exam was carried out on the uterus and no. of metrial glands.

Statistics:

The following parameters were examined to determine if covariance adjustments were necessary:
a) Body weights of F0 females on gestational Day 15
b) No. of live F1 and F2 pups/litter
c) Length of gestation period of the F0 and F1 females

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

During Days 15 - 20 of gestation there was a 16% decrease in mean weight gain compared to controls in the high dose group which was statistically significant (P ≤ 0.05).
In the same group, during lactational days 0 - 21 , there was a 13% decrease in mean body weight as compared to controls but this difference was not statistically significant (P > 0.05).

These slight decreases in weight gain occurred only in the high dose group and were sustained throughout the treatment period, and therefore were considered to be treatment-related effect.

In the low and middle dosage groups, mean body weights of F0 females were comparable to those of the control groups. During lactational days 14 - 21, there were weight losses of -7, -4, -7 and -2 g in the control, low middle and high dose respectively but none were treatment-related.
A reduction in maternal body weight or slight weight loss is not unusual among control dams during the 3rd week of lactation and may be related to a lesser demand for milk by F1 pups and therefore a reduced need for calories by the dam.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

There were no treatment-related effects on food consumption by F0 females.

Reproductive function / performance (P0)

Reproductive performance:

no effects observed

Description (incidence and severity):

There were no effects on reproduction performance and fertility as measured by:
Incidence of matings, time to mating, implants per female, post-implantation survival, parturition behaviour, date and time of delivery, incidence of pregnancy, number of F0 female with live pups and number of live pups.

Effect levels (P0)

Key result

Sex:

female

Basis for effect level:

body weight and weight gain

Remarks on result:

other: During Days 15 - 20 of gestation there was a 16% decrease in mean weight gain compared to controls in the high dose group which was statistically significant (P ≤ 0.05). In the same group, during lactational days 0 - 21 , there was a 13% decrease in mea

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

In both sexes, the mean post-natal Day 0 body weights in the high dose group were less than those of the controls. The mean body weight of the high dose female pups was 6.8%These slight decreases in weight gain occurred only in the high dose group and were sustained throughou less than that of the control group and mean body weight of high dose male pups was 4.8% less. Both differences were considered statistically significant (P ≤ 0.05) and considered to be treatment-related.

There were also slightly reduced mean body weights on post-natal Day 0 among female and male pups in the middle dosage groups (-3.4% and -3.2%) respectively compared to the control groups but they were considered to be incidental and unrelated to treatment for the following reasons. The slight difference was statistically significant (P ≤ 0.05) only among F1 female pups in the middle dose group and only when an adjustments were made for length of gestations. When analyses of Day 0 female pup weights was done on unadjusted data or data adjusted only for numbers of pups/litter, the difference in mean body weight between controls and the middle dose group on Day 0 were not significant (P > 0.05)

In the middle dose group of F1 male pups, the mean body weight on post-natal Day 0 was not significantly different from that of control group (P > 0.05) whether the data was unadjusted or adjusted (for number of pups/litter or length of gestation).

There were slight but statistically significant (P ≤ 0.05) treatment related decreases in mean body weight gains in the middle or high dose groups of F1 females and male pups during lactation.
.

Ophthalmological findings:

no effects observed

Sexual maturation:

no effects observed

Gross pathological findings:

no effects observed

Developmental neurotoxicity (F1)

Behaviour (functional findings):

no effects observed

Effect levels (F1)

Key result

Generation:

F1

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Remarks on result:

not determinable because of methodological limitations

Overall reproductive toxicity

Key result

Reproductive effects observed:

not specified

Treatment related:

not specified

Applicant's summary and conclusion

Conclusions:

There were sight treatment-related reductions in mean weight gain among F0 females in the high dose groups as compared to controls, throughout treatment [statistically significant (P ≤ 0.05) during days 15-20 of gestation]. There were no treatment-related effects on reproductive performance or fertility of F1 females. Necroscopy did not reveal any changes in the thoracic, abdominal or pelvic viscera of F1 dams.
There were no treatment-related deaths or physical signs among F1 male and female rats, either as pups or as adults. The mean post-natal Day 0 body weights of female and male F1 pups in the high does groups were slightly but significantly (P ≤ 0.05) reduced by treatment, as compared to controls. In the middle and high dose groups mean weight gains of F1 pups during lactation were slightly but significantly (P ≤ 0.05) reduced as compared to the control group. Both the reductions in weight gain were considered to be treatment-related. Opthalmic examinations of F1 rats did not reveal any treatment-related changes.
There were no effects of treatment on development of F1 rats or on behaviour in the open fields and swim maze tests. There were no treatment-related effects on post-weaning body weight gains of F1 rats, No treatment-related effects were observed in the testes and epididymides of F1 males. Reproductive performance and fertility of F1 rats as well as the status of F2 pups at parturition were not adversely affected by treatment.