Reaction mass of 1,2,3,4,4a,5,6,7-octahydro-2,5,5-trimethyl-2-naphthol and 4-(2,6,6-trimethyl-1-cyclohexen-1-yl)butan-2-one and 4-(2,6,6-trimethyl-2-cyclohexen-1-yl)butan-2-one

Endpoint summary

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Effects on fertility

Description of key information

The reproductive NOAEL was 10000 ppm as there were no test substance-related changes in estrous cycling in the female and mating and fertility in the males or females.  The NOAEL for viability and growth in the offspring was also 10000 ppm.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

Study duration:

subacute

Species:

rat

Quality of whole database:

K1

Additional information

The objectives of this study were to test for toxic effects/disturbances resulting from repeated exposure to Crl:CD(SD) male and female rats to POLYAMBROL® in the diet beginning before cohabitation, through mating and continuing for 49 days (male rats) or through parturition until Lactation Day 13 (female rats).  This study was designed to incorporate a reproduction/developmental toxicity screening test that is used to provide initial information on possible effects on male and female reproductive performance (e.g., gonadal function, mating behavior, conception, development of the conceptus and parturition).  The study also places emphasis on neurological effects as a specific endpoint and identifies the neurotoxic potential of a test substance, which may warrant further in-depth investigation.

The study design was as follows:

 

Experimental Design

Group No.	Test Material	Test Substance (ppm)	No. of Animals
			Males	Females
1	Carrier Control Substance	0	10	10
2	POLYAMBROL^®	2500	10	10
3	POLYAMBROL^®	5000	10	10
4	POLYAMBROL^®	10000	10	10
ppm = Parts per million.

 

The following parameters and end points were evaluated in this study: viability, clinical observations, body weights and body weight gains, food consumption, estrous cycle evaluations, cohabitation and mating, Functional Observational Battery (FOB), Motor Activity, clinical pathology parameters (hematology, coagulation, and clinical chemistry), thyroid hormone analysis, anogenital distance, nipple/areolae retention, organ weights, and histology and histopathology examinations.

Male Rats

The mean calculated doses for the male rats during the exposure period were 153.959, 300.235 and 572.937 in the 2500, 5000 and 10000 ppm exposure groups respectively.

All male rats survived until scheduled euthanasia.

There were no test substance-related clinical signs observed in the male rats.

There were no adverse changes in body weight, body weight gain or food consumption observed in the male rats during the exposure period.

There were no test substance-related effects on the Functional Observational Battery or motor activity evaluations in the male rats at exposure levels up to and including 10000 ppm.

All mating and fertility parameters in the male rats were unaffected by exposure to the test substance at levels up to and including 10000 ppm.

There were no test substance-related differences in hematology, coagulation and clinical chemistry values in the male rats at exposure levels up to and including 10000 ppm.

No test article-related gross findings were noted in the male rats.  

No test substance-related organ weight changes were noted in the male rats.  

In the kidneys of males at ≥ 2500 ppm, POLYAMBROL®-related findings included an increased incidence and/or severity of chronic progressive nephropathy (CPN) as well as accumulation of hyaline droplets in the tubules of the renal cortex and degeneration/necrosis of tubules, predominately in the region of the corticomedullary junction.  These findings are consistent with those reported in the literature where many chemicals have been found to exacerbate the incidence and/or severity of CPN and that hyaline droplet nephropathy was usually associated with a concomitant increase in the severity of CPN.  Since the findings in these males were not dose-dependent, there were no increases in blood urea nitrogen or creatinine in the serum clinical chemistry, and the relevance to humans are uncertain, the findings were not considered adverse.  

Examination of the testes revealed normal progression of the spermatogenic cycle and the expected cell associations and proportions in the various stages of spermatogenesis.

Female Rats and F1 Generation

The mean calculated doses for the female rats during the premating period were 166.688, 315.399 and 568.682 in the 2500, 5000 and 10000 ppm exposure groups respectively. The mean calculated doses for the female rats during the gestation period were 181.490, 355.265 and 672.249 in the 2500, 5000 and 10000 ppm exposure groups respectively.  The mean calculated doses for the female rats during the lactation period were 352.215, 649.204 and 1396.544 in the 2500, 5000 and 10000 ppm exposure groups respectively.

All female rats survived until scheduled euthanasia.

There were no test substance-related clinical signs observed in the female rats.

During the premating phase, there were statistically significant decreases in body weight gains at 5000 and 10000 ppm during the premating period (DSs 1 to 15).  There were also statistically significant decreases in food consumption observed at 2500, 5000 and 10000 ppm during the premating period.  On DSs 1 to 4, there were statistically significant decreases in body weight gains at 2500 and 5000 ppm and a statistically significant body weight loss observed at 10000 ppm.  There were also statistically significant decreases in food consumption on DSs 1 to 4 and 11 to 15 at 5000 ppm and at all intervals at 10000 ppm. 

During the gestation phase, there were statistically significant decreases in mean body weights at 5000 ppm on DGs 7, 14 and 17 in comparison with the control group values.  At 10000 ppm, there were statistically significant decreases in mean body weights at all intervals between DGs 3 to 17.  Body weight gains were also decreased or statistically significantly decreased at 2500, 5000 and 10000 ppm on DGs 0 to 3 and at 5000 and 10000 ppm on DGs 3 to 7.  There were decreases or statistically significant decreases in food consumption observed on DGs 0 to 3, 3 to 7 and 7 to 10 at 2500, 5000 and 10000 ppm.  There was also a statistically significant decrease in food consumption observed at 10000 ppm on DGs 14 to 17.

During the lactation phase, there were decreases or statistically significant decreases in mean body weights at 10000 ppm at all intervals between DL 0 and DL 10 and statistically significant decreases in food consumption at 10000 ppm on DLs 7 to 10 and 10 to 13.

All estrous cycling, mating and fertility parameters were unaffected by exposure to the test substance at exposure levels as high as 10000 ppm.

There were no test substance-related effects on the Functional Observational Battery and motor activity evaluations in the female rats at exposure levels up to and including 10000 ppm.

Mating occurred in 10, 10, 9 and 10 females and pregnancy occurred in 10, 10, 9 and 10 females at 0, 2500, 500 and 10000 ppm, respectively.

No test substance-related effects were noted on any natural delivery or ovarian and litter observation parameters in the P generation females. 

No clinical observations in the F1 generation pups were attributable to maternal exposure to the test substance at exposure levels as high as 10000 ppm.

Pup body weights were unaffected by maternal exposure to the test substance at doses up to and including 10000 ppm.  

The anogenital distances for the male and female pups were comparable across all exposure groups and there was no statistically significant difference.  There were no male pups observed with the presence of nipples on study.

There were no test substance-related differences in the hematology, coagulation or clinical chemistry values at exposure levels up to and including 10000 ppm.

There were no test substance-related gross findings, organ weight changes or any adverse histopathology in the P generation or F1 generation rats.  

Based on the results of this study, the no-observed-adverse-effect-level (NOAEL) for general toxicity was 10000 ppm in the male rats and was not established in the female rats.  In the females, reductions in body weight gain or a body weight loss and reduced food consumption were observed at all doses during the premating and gestation phase.  Reductions in mean body weights were observed at 5000 and 10000 ppm during the gestation phase and at 10000 ppm during the lactation phase. 

The reproductive NOAEL was 10000 ppm as there were no test substance-related changes in estrous cycling in the female and mating and fertility in the males or females.  The NOAEL for viability and growth in the offspring was also 10000 ppm.