1H-1,2,4-Triazole-1-carboxamide, 4-amino-N-(1,1-dimethylethyl)-4,5-dihydro-3-(1-methylethyl)-5-oxo-

Toxicity to reproduction

Administrative data

Endpoint:

two-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

6 January 1997 to 13 October 1997

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)

Version / remarks:

(1983)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPP 83-4 (Reproduction and Fertility Effects)

Version / remarks:

(1984)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OTS 798.4700 (Reproduction and Fertility Effects)

Version / remarks:

(1984)

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: JMAFF 59 NohSan No. 4200 (Guidance on toxicology study data for application of agriculture chemical registration) (1985)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

129909-90-9

IUPAC Name:

129909-90-9

Constituent 2

Reference substance name:

MKH 3586 Technical

IUPAC Name:

MKH 3586 Technical

Constituent 3

Reference substance name:

4-amino-N-tert-butyl-5-oxo-3-(propan-2-yl)-4,5-dihydro-1H-1,2,4-triazole-1-carboxamide

EC Number:

603-373-3

Cas Number:

129909-90-6

Molecular formula:

C10H19N5O2

IUPAC Name:

4-amino-N-tert-butyl-5-oxo-3-(propan-2-yl)-4,5-dihydro-1H-1,2,4-triazole-1-carboxamide

Details on test material:

- Name of test material (as cited in study report): MKH 3586 Technical
- Substance type: Powder
- Analytical purity: 98.2 - 99.1%
- Lot/batch No.: 05362/0005
- Expiration date of the lot/batch: confirmed stable for the duration of the study

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

not specified

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on mating procedure:

Animals were paired on a 1:1 basis for up to 21 consecutive days

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

10 weeks prior to mating, continuous throughout mating, gestation and lactation / dietary

Frequency of treatment:

Continuous

Details on study schedule:

Following ~10 weeks of treatment, male and females within each dose group were randomly paired and cohabitated (1:1) for up to 21 days to yield F1 littes of the first generation (P0).
On postpartum day 4, litters were culled to 8 pups leaving where possible equal number of male and female offspring.
At 21 days of age pups were weaned.

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
M & F: 0, 100, 500, 1000 ppm
Basis:
nominal in diet

Doses / concentrations 2

Remarks:

Doses / Concentrations:
M/F: 0, 6.4/7.3, 33.938.7, 73.2/84.0 mg/kg/day
Basis:
actual ingested

No. of animals per sex per dose:

30 animals/sex/dose

Control animals:

yes, plain diet

Results and discussion

Results: P0 (first parental generation)

Effect levels (P0)

1

Dose descriptor:

NOAEL

Remarks:

Maternal and offspring

Effect level:

ca. 100 ppm

Based on:

other: reductions in decreased body weights/body weight gains

Sex:

male

Basis for effect level:

other: equivalent to 6.4 mg/kg/day

Remarks on result:

other: Generation not specified (migrated information)

2

Dose descriptor:

NOAEL

Remarks:

Maternal and offspring

Effect level:

ca. 100 ppm

Based on:

other: reductions in decreased body weights/body weight gains

Sex:

female

Basis for effect level:

other: equivalent to 7.3 mg/kg/day

Remarks on result:

other: Generation: P & F1 (migrated information)

3

Dose descriptor:

NOAEL

Remarks:

reproductive

Effect level:

ca. 1 000 ppm

Based on:

other: no effects observed

Sex:

male

Basis for effect level:

other: equivalent to 73.2 mg/kg/day (highest dose tested)

Remarks on result:

other: Generation not specified (migrated information)

4

Dose descriptor:

NOAEL

Remarks:

reproductive

Effect level:

ca. 1 000 ppm

Based on:

other: no effects observed

Sex:

female

Basis for effect level:

other: equivalent to 84 mg/kg/day (highest dose tested)

Remarks on result:

other: Generation not specified (migrated information)

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

F₁GENERATION

Parental clinical signs and mortality:

No test material related clinical signs of toxicity were observed in males or females during pre-mating, mating, gestation or lactation. No mortality was observed.

 

Parental bodyweight:

Pre-mating and mating phases: statistically significant effects (p<0.05 or p<0.01) on body weight were noted in males of the 500 and 1000 ppm dose groups. At the start of the pre-mating phase the body weights of these two groups were statistically greater than the control. However for all remaining time points (days 7 through to 105) the body weights of the males in the 1000 ppm group were less than the control. In comparison the body weights for the 100 and 500 ppm dose groups were not consistently affected. For females of the 1000 ppm group body weights were statistically significantly decreased relative to the control on pre-mating days 7, 28, 35, 49, 56, 60 and 70. At 500 ppm, whilst not significant, body weight was decreased at all time points following the day 0 measurements. Body weights of the 100 ppm group was unaffected by treatment.

Gestation phase: body weight of females in the high dose group were significantly decreased compared to the controls. Although no significant, body weights in the 500 ppm group were consistently lower throughout gestation compared to the control.

Lactation: body weight of females in the high dose group were significantly decreased compared to the controls. Although only significantly reduced on day 14, body weight was decreased for each time point in the 500 ppm dose group.

 

Parental food consumption:

Pre-mating and mating phases:statistically significant decreases during the first week of the pre-mating phase in both males and females of the 500 and 1000 ppm dose groups.

Lactation phase:although not significant, a 24% decrease in food consumption (compared to the control) in the 1000 ppm dose group during the first 4 days of the lactation phase was observed (this may have contributed to the decrease in body weight discussed above). Also observed in this group were significantly increased food consumption from days 4-7, 7-14 and 14-21.

 

Table 7.8.1-1: Selected body weight and food consumption data for F₁generation (%relative change vs. control)

Dose (ppm)	100	500	1000	100	500	100
Days	Males			Females
BODY WEIGHT Gestation (%relative change vs. control)
0	-	-	-	+0.5	-2.7	-4.6
6	-	-	-	+0.6	+1.2	+6.3*
13	-	-	-	0.0	+3.0	+8.0**
20	-	-	-	-1.6	-3.3	-8.1**
Lactation
0	-	-	-	-0.5	-2.6	-7.3**
4	-	-	-	+0.8	-4.5	-22.0**
7	-	-	-	-1.8	-5.9	-13.6**
14	-	-	-	-0.9	-7.2*	-15.3**
21		-	-	+0.2	-3.8	-7.4**
FOOD CONSUMPTION Pre-mating
0-7	-3.2	-6.5*	-14.0**	-1.4	-9.7**	-15.1**
28-35	+1.1	0.0	+3.7	0.0	+6.2	+7.7
56-36	+8.9	+9.2*	+12.2**	0.0	-2.6	+2.8
63-70	-3.3	-3.3	+1.0	-0.3	-0.8	+2.3
Lactation (days)
0-4	-	-	-	-4.8	-3.9	-24.2**
4-7	-	-	-	-7.5	+9.0	+30.0**
7-14	-	-	-	-7.0	+12.0	+13.9*
14-21	-	-	-	-2.1	+8.5	18.9**

* p<0.05; ** p<0.01

 

Reproductive function and performance:

There were no treatment related effects on mating, fertility or gestation indices. There were no effects observed on the number of oestrus cycles, oestrus cycle length, days to insemination, gestation length or the total number of implantations.

 

Parentalpost mortemresults:

No gross necropsy observations suggestive of a relationship to treatment with MKH 3586. There were no histological lesions, either non-neoplastic or neoplastic considered to be related to dietary administration of the test material. Effects on organ weights were limited to a statistically significant effect on the liver/body weight ratio, observed in both males and females of the 1000 ppm dose group (increased to 11% relative to the control in both cases). However no effect on the absolute liver weight was observed at this dose level.

 

There were no treatment related effects on male reproductive organs.

 

Offspring clinical signs:

No test material related effects were observed.

 

Offspring body weights: 

Lactation phase: significantly decreased (p<0.01) on lactation day 4 through to 21 for the males and females of the 1000 ppm and to a lesser extent (p<0.05) for males in the 500 ppm group. For females in the 500 ppm group significant decrease (p<0.01) was also observed in the 500 ppm group.

 

Table 7.8.1-2: Selected body weight during lactation for F₁pups (%relative change vs. control)

Dose (ppm)	100	500	1000	100	500	100
Days	Males			Females
0-4	+15.6	0.0	46.9**	+12.5	-6.3	-46.9**
4-7	-8.3	-15.0*	-35.0*	-7.0	-12.3*	-33.3**
4-21	-4.8	-10.4*	-22.7**	-1.8	-10.9**	-23.0**
7-14	-6.0	-9.3*	-20.0**	-3.4	-10.3	-6.8

* p<0.05; ** p<0.01

 

Litter effects:

No significant effects on litter size, total number of pups born, sex distribution, mean number of viable pups or the number of stillborn pups. Although not significant there was an increase in the number of pups found dead in the 500 ppm group vs. the control. Although high, 7 of the 14 pups which died were from the same litter, leaving only 7 remaining found dead pups between 5 other dams (which is consistent with other groups), resulting in a similar incidence. No significant effects were observed on the live birth, viability, lactation or birth indices.

 

Offspringpost mortemresults:

No test material related effects were observed.

 

F₂GENERATION

Parental clinical signs and mortality:

No test material related clinical signs of toxicity were observed in males or females during pre-mating, mating, gestation or lactation. No mortality was observed.

 

Parental bodyweight:

Pre-mating and mating phases: statistically significant effects were noted in the males of 500 ppm and 1000 ppm groups. Although body weights in the 500 ppm dose group were reduced at every time point, there was a statistically significant difference on days 14, 21, 28, 35, 42, 49, 77, 84 and 91. In comparison, statistically significant reductions in the 1000 ppm were reduced at every time point during the pre-mating and mating phases.

For females, statistically significant decreases in body weight were observed in the 1000 ppm group at every time point during the pre-mating phase. In the mating phase statistically significant decreases were observed on days 28, 49, 56 and 70 in the 500 ppm group.

Lactation phase: statistically significant decreases in the 1000 ppm dose group were observed at each time point. For the 500 ppm group reductions were noted for all time points with statistically significant decreases observed on days 4, 7 and 14. 

 

Parental food consumption:

Pre-mating and mating phases:statistically significant increases were observed on days 7-14, 14,-21, 28-35, 35-42, 42-49, 49-56 and 56-63 for high dose group males. Females of the same group had statistically significant increases on days 28-35, 49-56, 56-63 and 63-70.

Lactation phase:statistically significant increases observed on days 4-7, 7-14 and 14-21.

 

Table 7.8.1-3: Selected body weight and food consumption data for F₂generation (%relative change vs. control)

Dose (ppm)	100	500	1000	100	500	100
Days	Males			Females
BODY WEIGHT Gestation
0	-4.4	-4.4	-12.2**	-12.4	-4.6	-14.2**
28	-0.8	-6.8*	-10.2**	+0.7	-6.1*	-16.0**
56	-1.4	-7.9	-9.0**	-0.5	-2.0*	-12.8**
70	+0.9	-5.2	-8.0**	-0.4	-5.9*	-12.5**
84	0.0	-7.7*	-8.3**	-	-	-
98	-0.2	-4.9	-7.9*	-	-	-
Lactation
0	-	-	-	-1.1	-4.8	-10.8**
4	-	-	-	-2.1	-8.2**	-12.8**
7	-	-	-	0.9	-6.3*	-10.7*
14	-	-	-	+0.1	-7.1**	-10.4**
21		-	-	-1.2	-4.6	10.4**
FOOD CONSUMPTION Pre-mating
+..7	+6.0	+3.1	+7.8	+2.7	+1.5	+4.1
28-35	-1.4	+4.4	+7.2**	-1.4	+1.8	+5.3
56-36	+6.0	+9.2	+9.2*	+2.3	+2.3	+5.0*
63-70	-4.6	-4.0	+2.1	+0.8	+3.3	+10.3**
Lactation (days)
0-4	-	-	-	+2.7	+2.7	+13.1
4-7	-	-	-	+7.7	+5.8	+22.8**
7-14	-	-	-	+4.2	+8.0	+17.9**
14-21	-	-	-	-3.1	+1.1	+11.2**

* p<0.05; ** p<0.01

 

Reproductive function and performance:

There were no treatment related effects on mating, fertility or gestation indices. There were no effects observed on the number of oestrus cycles, oestrus cycle length, days to insemination, gestation length or the total number of implantations.

 

Parentalpost mortemresults:

A statistically significant effect on liver/body weight was observed in the females in the 500 and 1000 ppm groups (increase of 9% and 15% respectively, vs. control). The terminal body weight was statistically reduced in the 1000 ppm group, with a % decrease of 10% (vs. control).

 

There were no treatment related effects on male reproductive organs. Test material related histological lesions were found in the liver of the 1000 ppm dose group females. As in the males, these lesions consisted primarily of minimal hepatocytomegaly.

 

Table 7.8.1-4: Selected organ weights and histopathological findings for the F₁generation

Dose (ppm)	0	100	500	1000	0	100	500	1000
	MALES				FEMALES
BODY WEIGHT
Terminal BW (g)	414.6	424.4	398.4	387.6*	295.8	293.1	283.5	265.8*
Liver (g)	18.589	18.824	18.582	19.923	17.370	17.575	18.062	17.977
Liver /BW (%)	4.467	4.431	4.655	5.122*	5.861	5.994	6.370*	6.736*
HISTOPATHOLOGY Liver
Hepatocytomegaly	0 (30)	0 (30)	0 (30)	10 (30) *	0 (30)	0 (30)	0 (30)	3 (30)

 * p<0.05; ** p<0.01

  

Offspring clinical signs:

No test material related effects were observed.

 

Offspring body weights:

Lactation phase: from day 7 until weaning the 1000 ppm dose group and from day 14 until weaning the 500 ppm group (both males and females) exhibited statistically significant decreases in body weight vs. control.

 

Litter effects:

No significant effects on litter size, total number of pups born, sex distribution, mean number of viable pups or the number of stillborn pups. No statistically significant effects were observed on the birth, live birth, viability o rlactation indices. There was an increase in dead pups found in the 500 ppm dose group with 18 pups from 7 litter found dead compared to 3 pups form 3 litters in the control. Also observed in this group was a statistically significant decrease in the pup body weights were observed in both the 500 and 1000 ppm groups.

 

Offspringpost mortemresults:

No test material related effects were observed.

Applicant's summary and conclusion

Conclusions:

Based on the results of this study both the maternal and offspring toxicity NOAELs were considered to be 100 ppm (equivalent to 6.4/7.3 mg/kg/day [males/females]), based on reductions in decreased body weights/body weight gains in both sex. No effects on reproductive parameters were observed up to the maximum dose tested, therefore the reproductive NOAEL is considered to be 1000 ppm (equivalent to 73.2/84.0 mg/kg/day [males/females]).

Executive summary:

MKH 3586 was administered orally via gavage to 30 Sprague-Dawley rats/sex/dose at nominal doses of 0, 100, 500 or 1000 ppm in the diet. These doses were equivalent to 0, 6.4, 33.9 or 73.2 mg/kg/day for males and 0, 7.3, 38.7 or 84 mg/kg/day for females respectively. The P and F₁ parents were given the test diets for 10 weeks prior to mating to produce the F₁ and F₂ litters.  F₁ pups were weaned at 21 days of age and approximately 30 pups/sex/group were randomly selected as parents of the F₂ generation. Sperm parameters were not evaluated in the parental males and sexual maturation and developmental landmarks were not evaluated in the offspring.

 

Parental toxicity was evidenced with decreased body weights and body weight gains seen at both 500 and 1000 ppm in both generations. During pre-,mating food consumption was significantly decreased in both males and females of the 500 and 1000 ppm groups. In contrast, significant increases in food consumption were observed at various times during the pre-mating phase of the second generation for both males and females in the 1000 ppm group and during lactation in females at 1000 ppm. terminal body weights were decreased (p<0.05) in F₁ males and females, due in part to reduced terminal vody weights. Minimal to slight hepatocytomegaly was noted in F₁ males (10/30) compared to controls (0/30) , but no microscopic pathology consistent with liver toxicity was observed., no treatment related finding were observed at 100 ppm.

 

No effects of treatment on the birth, live birth, viability or lactation indices, sex ratio or gross pathology in the F₁ or F₂ pups were observed. Decreased body weights were observed on PND 14 and 21 in F₁ and F₂ pups. At 1000 ppm, decreased (p<0.05) body weights were noted on PND 4, 7, 14 and 21 in F₁ pups and on PND 7, 14 and 21 in F₂ pups.

 

Based on the results of this study both the maternal and offspring toxicity NOAELs were considered to be 100 ppm (equivalent to 6.4/7.3 mg/kg/day [males/females]), based on reductions in decreased body weights/body weight gains in both sex. No effects on reproductive parameters were observed up to the maximum dose tested, therefore the reproductive NOAEL is considered to be 1000 ppm (equivalent to 73.2/84.0 mg/kg/day [males/females]).