[No public or meaningful name is available]

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:

From September 24,1997 to 29 January 1998

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP compliant study conducted according to recognised test methods

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1,2-Benzenedicarboxylic acid, di-C9-11-branched and linear alkyl esters

EC Number:

271-085-1

EC Name:

1,2-Benzenedicarboxylic acid, di-C9-11-branched and linear alkyl esters

Cas Number:

68515-43-5

IUPAC Name:

dioctyl phthalate

Details on test material:

- Name of test material: BISOFLEX L911P
- Formal name: 1,2 benzene dicarboxylic acid , di C9-C11 alkyl esters
- Physical state:liquid oily
- Analytical purity:99.2%
- Lot/batch No.:PLA/S20517/97
- Storage condition of test material: ambient temperature

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:Charles river UK Limited
- Age at study initiation:5 weeks
- Weight at study initiation: 145 - 228 g (males) , 115-198 g (female)
- Fasting period before study:
- Housing: TR18 cages or RB3 from arrowmight biosciences ; stainless steel
- Diet:ad libitum
- Animal diet quality: LAD 2 SQC manufactured by special diet services limited. This powdered diet contained no added antibiotic or other chemotherapeutic or prophylactic agent.
- Water: ad libitum
- Water quality: is governed by regulation published by department of the environment. At approximately six-monthly intervals , water was routinely sampled for analysis by a laboratory independent of the supplier, for selected chlorinated pesticides and polychlorinated biphenyl contaminants.
- Acclimation period:5 days
- Healty check: during the acclimatation period
- identification: by tail tattoo
ENVIRONMENTAL CONDITIONS
- Temperature (°C):21°C
- Humidity (%):42-71%
- Air changes:filterd fresh air
- Photoperiod : 12 hours cycle dark/light

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet: The required dietary concentrations were prepared by direct dilution of the premix with further quantities of untreated diet. Blending was achieved by mixing in a Turbula Mixer for a minimum period of 6 minutes (for a least 100 cycles).
- Mixing appropriate amounts with: A pre-mix of diet was prepared by weighing out the quantity of D911P and adding an approximately equal amount of untreated diet. This mixture was then stirred prior to the addition of a further quantity of diet, approximately equal to the weight of the mixture; this process was repeated until the mixture did not readily cohere. The admixture was then passed through a 1 mm sieve. Further quantities of untreated diet were added until the required quantity of premix was obtained, the premix was then stirred thoroughly. Blending was achieved by mixing in Turbula Mixer for a minimum period of 6 minutes (for at least 100 cycles)

VEHICLE
- Justification for use and choice of vehicle:to simulate the conditions of human exposure
- Concentration in vehicle:0 ppm (control) , 1000 ppm , 5000 ppm , 10000 ppm , 20000 ppm( was selected as the initial concentration for the highest dosage group, but this was reduced to 10000 ppm after 6 weeks of treatment [43 days] of F0 generation , following poor bodyweight gain by males)

Details on mating procedure:

free mating inside the cage

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Specified formulations prepared before the preliminary study were analysed to assess the homogeneity and stability of the test substance in the diet matrix at concentrations of 100 and 20000 ppm. The results indicated that the mixing procedure generated homogenous distributions of the test material in powdered diet and that the material was stable in the diet under conditions of use. No further homogeneity or stability analyses were performed in this study.
Single samples (nominally 200g) were taken from all groups/sex (2 assays from each sample) to check for the content of the compound at weeks 1, 8 11 14, 18, 28; and 31 of the study The results of the test diet formulations analysed during the study were within 12% of the nominal concentrations
confirming the accuracy of the formulation .
The analytical procedure validation, the homogeneity and stability during ambient temperature storage for 22 days was confirmed for D911P in LAD 2 SQC diet formulation at nominal concentrations of 100 ppm and 20000 ppm during an earlier study. The experimental procedure and the analytical results obtained were presented in Huntingdon Life Sciences report SEB 003/972423 and are included in this report for completeness. The samples were analysed using a method supplied by the Sponsor (reference 'Gas Chromatographic Analysis of L79 Phthalate for C7- C9 Phthalate Esters' supplied in a facsimile message dated 23 January 1997) and modified at Huntingdon Life Sciences (SEB/FA/M26/97 issue 01/110497). The method of analysis for D91IP in LAD 2 SQC diet involved methanol extraction, methanol dilution and injection of the diluted test samples on to a high-performance liquid chromatograph (HPLC) with ultra- violet detection. The amount of D911P in the test samples was quantified by reference to calibration standards of low concentrations.

Duration of treatment / exposure:

For this purpose D911P was administered continuously in the diet at concentrations of 1000, 5000 or 10000 ppm to groups of rats throughout the two generations. The highest dosage group animals were given 20000 ppm of D911P for approximately six weeks (43 days) at the start of the Fo generation but this was reduced to 10000 ppm because of a marked reduction in bodyweight gain of the males. A fourth group received the basal diet without the test material and served as the Control.
The Fo generation, which comprised 28 males and 28 females in each group, received the treated diet for 10 weeks before pairing and throughout mating, gestation and lactation. From the F1 litters, 28 male and 28 female offspring were selected to form the F1 generation. Both sexes received
treatment for a minimum of 10 weeks from the formal commencement of the F1 generation (approximately 28 days of age), throughout pairing, gestation and lactation.Surplus F1 offspring and F2 offspring were killed on Day 25 of age and selected organs were weighed and retained in fixative at necropsy.

Frequency of treatment:

the food was added ad libitum. The required dietary concentrations were prepared by direct dilution of the premix with further quantities of untreated diet..The formulation were prepared generally on weekly basis.

Details on study schedule:

no data

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
1000 ppm
Basis:
nominal in diet

Doses / concentrations 2

Remarks:

Doses / Concentrations:
5000 ppm
Basis:
nominal in diet

Doses / concentrations 3

Remarks:

Doses / Concentrations:
10000 ppm
Basis:
nominal in diet

No. of animals per sex per dose:

Chemical intake for Fo males and females in the first six weeks of treatment when the dietary concentration was 20000 ppm was initially in excess of 2000 mg/kg/day and exceeded 1300 mg/kg/day throughout the first six weeks of treatment. Intakes were halved when the dietary concentration was reduced to 10000 ppm, falling to about 600 mg/kg/day for males and 700 mg/kg/day for females at the point of pairing. In the second generation, intakes at 10000 ppm were in excess of 1800 mg/kg/day during the first week after selection, falling to about 600-800 mg/kg/day by the time of pairing. Chemical intakes for Fo animals at 5000 ppm were about 600 mg/kg/day for both sexes at the start of treatment falling to around 300 mg/kg/day by the time of pairing. In the F1 generation both sexes during the first week after selection received around 900 mg/kg/day falling to around 300 mg/kg/day for males and 400 mg/kg/day for females prior to pairing. At 1000 ppm intake for both sexes of the Fo generation was around 120 mg/kg/day at the start of treatment falling to about 60 mg/kg/day at the end of the pre-pairing period. In the F1 generation both sexes during the first week after selection received around 180 mg/kg/day falling to around 60 mg/kg/day for males and 70 mg/kg/day for females prior to pairing. Female chemical intake during gestation remained similar to before pairing levels but doubled during lactation, reflecting increased food intake at the time of peak physiological demand.

Control animals:

yes, concurrent no treatment

Details on study design:

the fourth animal group was treated without test material

Examinations

Parental animals: Observations and examinations:

During the study the rats were examined by: bodyweight (twice a day), food consumption, chemical intake, estrous cycles and gestation. After death they were examined for any macroscopic changes , organs weights and histopathology.

Oestrous cyclicity (parental animals):

The regularity and duration of the oestrous cycles were unaffected by the presence of D911P in the diet at concentrations up to 10000 ppm in both generation The timing of sexual maturation of the f1 animals and pre-coital interval and fertility in both generations are unaffected by treatment.

Sperm parameters (parental animals):

The quality of epididymal sperm and the numbers of homogenisation resistant spermatids was unaffected by treatment in either the Fo or the F1 generation males.

Litter observations:

Litter size ,offspring viability sex ratio and bodyweight on Day 1 of age were not directly affected by treatment for either the F1 or the F2 litters At 5000 ppm in the second generation and at 10000 pm in both generations overall weight gain of pups was reduced with differences in gain compared to the control being most pronounced during the second week of age.

Postmortem examinations (parental animals):

Findings in the Fo and F1 generation considered to be related to treatment with D911P were generally restricted to the livers of males treated at 10000 ppm. The range of findings observed for the high dosage group males is indicative of hepatotoxicity of the periacinar hepatocytes with consequential increased cell turnover resulting in regenerative hyperplasia. The development of altered cell foci in males at this dosage is probably a consequence of the increase turnover of hepatocytes, while bile duct proliferation is probably associated with the altered architecture of the liver.

Postmortem examinations (offspring):

For F2 offspring at 10000 ppm there was a significant decrease in the absolute weights of the thymus and spleen, however differences from Control were not evident when these weights were expressed relative to bodyweight. These differences may be due to the treatment effect on bodyweight observed for these animals at Day 25 rather than a direct effect of treatment on the organs themselves

Statistics:

Significance tests , employing of variance followed by an inter-group comparison with the control, were performed on the following parameters: Bodyweights and bodyweight range.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

no effects observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

bodyweight decrease

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

bodyweight decrease

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

increase cell turnover

Other effects:

effects observed, treatment-related

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS):The general condition of animals was similar in all groups and clinical signs were largely restricted to areas of hair loss, coat staining and to a lesser extent scabbing.
There were three mortalities in the Fo generation. One Control male (number 1019) was killed during week 6 for reasons of animal welfare, due to a persistent ulceration on its upper dorsal surface. One female (number 1177) receiving 5000 ppm was killed after showing hunched posture, piloerection, thin appearance and apparent blood and urine staining on the ventral body surface on Day 5 of lactation (Week 15 of treatment). Bodyweight on Day 4 of the majority of the litter was lower than that recorded on Day 1 and the litter was showing signs of neglect (pups cold, unfed and under active) on Days 4 and 5 of lactation. Necropsy failed to reveal an obvious cause for the animals' condition. One female (number 1199) receiving 10000/20000 ppm was killed during week 16 after showing apparent bleeding from the vagina 2 days after parturition. Other clinical signs included hunched posture, piloerection, cold to touch, pallor and under activity. Necropsy findings were unremarkable. The incidence and circumstances of the deaths of the two treated females did not indicate any association with D911P.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS):
Bodyweight of males:At 20000 ppm mean bodyweight gain of males was significantly lower than the concurrent Control; the divergence being such that it was considered necessary to reduce the dietary exposure for this group during the seventh week of treatment to 10000 ppm, in order to safeguard the reproductive objectives of the study. Subsequent weight gain stabilised; however, the deficit in bodyweight gain was never recovered and therefore the mean values for overall gain and absolute bodyweight of these animals at termination was significantly lower than the Control.Mean bodyweight gain of males at 5000 and 1000 ppm were not adversely affected by treatment and were generally comparable to those of the Control.

Bodyweight of females:At 20000 ppm mean bodyweight gain of females was lower than the concurrent Control and, although this effect of treatment was not as marked as observed for the males, differences had attained statistical significance by the end of the third week of treatment. With the reduction in dietary exposure to 10000 ppm during the seventh week of treatment subsequent weight gain to the end of the pre-pairing period was essentially similar to the Control; as observed with the males, however, the deficit in bodyweight gain was never recovered and therefore the mean values for overall gain and absolute bodyweight of these animals at the end of the pre-pairing period remained significantly lower than the Control. At 5000 ppm initial mean bodyweight gain of females .was similar to that of the Control; however, as the pre-mating period progressed some divergence was apparent, although differences never attained statistical significance.
There was no obvious adverse effect of treatment at 1000 ppm on bodyweight gain of females prior to pairing.
Overall bodyweight gain during gestation was similar in all groups and was not influenced by treatment. Lower bodyweight gain was noted in treated groups during the first week of gestation; however this was considered likely to be a reflection of the general pattern established in the week preceding pairing and the slightly lower bodyweight at 5000 and 10000/20000 ppm. In the absence of any effects on overall bodyweight gain during gestation, or effects on subsequent fertility, litter data or pup weights at Day 1 this finding is not considered to be of any toxicological significance.
The pattern of bodyweight change during lactation was similar in all groups with the exception that at 10000 ppm the drop in bodyweight frequently observed during the last week of lactation did not materialise. Again, the significance of this finding is unclear, as the bodyweight gain of F1 offspring
during this period appeared unaffected, but a similar response during lactation was observed at this dosage in the F1 generation; nevertheless, it is not considered to represent an adverse effect of treatment.

TEST SUBSTANCE INTAKE (PARENTAL ANIMALS):For animals receiving 20000 ppm until Week 7 chemical intake for males ranged from 2379 mg/kg/day in Week 1 to 1366 mg/kg/day in Week 6 and for females ranged from 2403 to 1610 mg/kg/day over the same period. Following the reduction in dietary inclusion to 10000 ppm chemical intake during the remaining pre-pairing period fell by approximately half, then continued to show the natural decline associated with change in growth rate: food intake as animal's mature; intake immediately prior to
pairing was 619 mg/kg/day in males and 696 mg/kg/day in females. Chemical intake during the pre-pairing period by animals in the lower treatment groups was in proportion to the dietary concentrations, reducing steadily as the animals became older. At 5000 ppm the achieved ranges for males were 607 mg/kg/day in Week 1 to 280 mg/kg/day in Week 10 and 606 to 328 mg/kg/day for females over the same period. At 1000 ppm the achieved ranges over the same period were 121 to 56 mg/kg/day for males and 123 to 63 mg/kg/day for females. Chemical intake by females during gestation was slightly higher than in the preceding period before pairing and approximately doubled during mid lactation in line with the increase in food intake at peak physiological demand.
Overall the intended 5 and 4/2 fold differences between treatment groups was maintained at any given point throughout the study but, with the lowering of the interval between the intermediate and high dosage group, there were times when animals within the intermediate group reached intake levels
approaching those of the highest dosage at a different stage of the study.

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS): There was no obvious adverse effect of D911P on the regularity and duration of the oestrous cycles at any of the dietary inclusion levels investigated.

REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS):The quality of the epididymal sperm, as assessed by numbers motility and gross morphology was unaffected by treatment with D911P at any of the inclusion levels investigated and these was no evidence of an effect of treatment upon the homogenisation resistant spermatids within the testis. It was noted that male numbers 1021 (Control), 1049 (Group 2) and 1077 (Group 3) were siblings and all three showed a low percentage of progressively motile sperm and failed to induce pregnancy in their female partners.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS):There was no adverse effect of treatment on pre-coital interval, the majority of animals mating within four days of pairing i.e. at first oestrus opportunity. Fertility was not affected by treatment with D911P at any of the dosages investigated.

ORGAN WEIGHTS (PARENTAL ANIMALS):At 10000/20000 ppm the mean bodyweight of males at termination was significantly lower than that of the Control complicating the assessment of possible effects of treatment on organ weights. For males at 1000 and 5000 ppm and females at all dosages terminal bodyweight was comparable to the control.
For males at 10000/20000 ppm a number of absolute organ weights (brain, liver, kidneys, spleen, adrenals, epididymides, prostate and seminal vesicles) and bodyweight relative organ weights (brain, kidneys, spleen, thymus, testes, epididymides and seminal vesicles) were statistically significant,
when compared with the concurrent Control. In general bodyweight relative organ weights were considered to give a better indication of effects of treatment than absolutes at this inclusion level because of the marked effect on bodyweight. The most notable differences from Control were considered to be increases in the relative weight of the thymus, spleen and kidneys; however in the absence of any histopathological changes the toxicological significance of these findings is unclear. For males at 5000 and 1000 ppm there were no obvious adverse effects of treatment on organ
weights.
Amongst females, increased liver weight at 5000 and 10000/20000 ppm was considered to be the most noticeable effect, particularly as it suggested a different response from the males. Decreased absolute and relative adrenal, thymus and, to a lesser extent, spleen weights at 10000/20000 ppm may also be of some toxicological significance but, as for males, in the absence of any histological changes this is not clear. Excluding the increased liver weight at 5000 ppm organ weights at this dosage and at 1000 ppm were not obviously affected by treatment.

GROSS PATHOLOGY (PARENTAL ANIMALS): macroscopic necropsy findings considered to be related to treatment were predominantly restricted to
liver changes amongst males receiving 10000/20000 ppm. The majority of livers typically were pale and showed areas of macroscopic change, some also had an irregular surface. For females at this level a few animals showed enlargement of the liver and accentuation of the lobular pattern however,
the findings common to their male counterparts were generally not evident. For males at 1000 and 5000 ppm liver changes were generally restricted to swelling, with only the occasional animal at 5000 ppm showing the changes typical of the high dosage. For females at 1000 and 5000 ppm liver findings were generally unremarkable. Neither the type, incidence nor distribution of findings for other organs and tissues at necropsy
indicated any adverse effects of treatment at any of the inclusion levels investigated.

HISTOPATHOLOGY (PARENTAL ANIMALS):Histopathological findings in the Fo generation considered to be related to treatment with D911P were
restricted to changes in the livers of males at 5000 ppm and of both sexes at 10000/20000 ppm.
The range of findings observed for the high dosage group males is indicative of hepatoxicity 0f the periacinar hepatocytes with consequential increased cell turnover resulting in regenerative hyperplasia. The development of altered cell foci and the single occurrence of a hepatocellular adenoma in males at this dosage is probably a consequence of the increase turnover of hepatocytes, while bile duct proliferation is probably associated with the altered architecture of the liver. Changes in the liver may be associated with an increase in peroxisomal enzymes which has been demonstrated
in the livers of five treated F1 animals at this dosage. In contrast to the males, females treated with D911P were markedly less affected with only a low incidence of periacinar hepatocytic vacuolation, periacinar hepatocytic hypertrophy and periacinar hepatocytic necrosis being observed at the high
dosage group.
There were no other microscopic findings observed that were considered to be related to treatment.
It was noted that females receiving 10000/20000 ppm had a lower incidence of dilated uteri and a lower incidence of uteri with dilated endometrial glands. Dilatation of the uterus reflects the normal physiological response of the uterus to the hormonal status of the animal during the oestrous cycle.
As these animals were still in the immediate post lactation phase at the time of necropsy, it is unlikely that the oestrous cycle was fully established or regular in many of the animals. The lower incidence of dilated uteri at the highest dosage is considered to be fortuitous and of no toxicological
significance.

OTHER FINDINGS (PARENTAL ANIMALS)
Gestation length and parturition :
The majority of females gave birth to live young after gestation periods of between 22 and 23.5 days. Within this range there appeared to be a slight shift in treated animals towards having a slightly shorter gestation period, the trend attaining statistical significance. The biological significance of this
observation in this study is uncertain as there appeared to be no adverse effect on survival at parturition or on bodyweight at Day 1, however it was replicated in the F1 generation and may have been linked to the lower bodyweights of females at 5000 and 10000 ppm.
There were no indications of any adverse effects of treatment upon the parturition process.

Effect levels (P0)

Dose descriptor:

NOAEL

Effect level:

ca. 10 000 ppm

Based on:

test mat.

Sex:

male/female

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):

decease

Sexual maturation:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

male liver

Histopathological findings:

effects observed, treatment-related

Description (incidence and severity):

increase liver cell turnover

Details on results (F1)

VIABILITY (OFFSPRING): Litter size and offspring viability:
The number of implantations sites recorded at necropsy were similar for all groups and there was no obvious adverse effect of treatment on in-utero survival, as assessed by total litter size and live litter size at Day 1 of age, or subsequent pup survival to weaning.
Indices of offspring viability were largely influenced by the incidence of total litter losses (2, 3, 3 and 2 litters for Groups 1 to 4 respectively), in addition to the death of a dam (see mortalities) at 5000 and 10000 ppm. The majority of litter deaths occurred during the first week of age with few deaths after
litter size standardisation at Day 4 and, in the majority of cases, litters that died were small in bodyweight when first seen and were considered to be cold, unfed and underactive before eventual death.

CLINICAL SIGNS (OFFSPRING): Necropsy of offspring which died before weaning revealed absence of milk in the stomach as the only consistent finding. This finding is commonly seen in neonates which die at an early age. Neither the type, incidence nor distribution of findings at necropsy of offspring at 25 days of age indicated any adverse effect of treatment with D911P.

BODY WEIGHT (OFFSPRING): Bodyweights of male and female offspring at Day 1 of age was unaffected by treatment at any dosage investigated.
At 10000 ppm overall bodyweight gain of both sexes to weaning at Day 21 of age was marginally lower than Control (although differences failed to attain statistical significance) principally due to a slightly lower mean gain between Day 7 and 14 of age. A similar effect on bodyweight gain during this
period was evident in the F2 offspring.
At 1000 and 5000 ppm bodyweight gain of both sexes to weaning was essentially similar to Control.

SEXUAL MATURATION (OFFSPRING): The quality of epididymal sperm and the numbers of homogenisation resistant spermatids was unaffected by treatment in either the Fo or the F1 generation males.

ORGAN WEIGHTS (OFFSPRING): At 10000 ppm, although mean bodyweight was slightly below that of the Control counterparts, there was a marked increase in mean absolute liver weight for both sexes when compared to Control, differences attaining statistical significance. This difference was very evident when the organ weight was expressed as a percentage of the offspring bodyweight A similar increase in mean liver weight of the offspring was also observed for the F2 generation.
At 5000 ppm absolute liver weight for both sexes was slightly higher than the concurrent Control; further divergence from Control was again evident when organ weight was expressedes a pereontage of bodyweight.
Liver weight at 1000 ppm was similar to the Control.
There was no obvious adverse effect of treatment on the absolute or relative organ weight of the brain, spleen or thymus for either sex at any of the dosages investigated lower thymus weight was nosed at 5000 and 10000 ppm for both sexes however, as organ weight expressed as a percentage of
bodyweight values were essentially similar to control; there was no conclusive association with treatment.

GROSS PATHOLOGY (OFFSPRING)

HISTOPATHOLOGY (OFFSPRING): Histopathological findings in the F1 generation considered to be related to treatment with D911P
were restricted to changes in the livers of males at 5000 ppm and of both sexes at 10000 ppm. The range of findings observed for the high dosage group males is indicative of hepatotoxicity of the periacinar hepatocytes with consequential increased cell turnover resulting in regenerative
hyperplasia. The development of altered cell foci in males at this dosage is probably a consequence of the increase turnover of hepatocytes, while bile duct proliferation is probably associated with the altered architecture of the liver. Changes in the liver may be associated with an increase in peroxisomal enzymes, which has been demonstrated in the livers of five treated F1 animals at this dosage. Males at 5000 ppm and females at 10000 ppm livers were less affected and showed periacinar hepatocytic vacuolation, periacinar hepatocytic hypertrophy and periacinar hepatocytic necrosis the females in particular showing only a low incidence of findings.
There were no other microscopic findings observed that were considered to be related to treatment..

OTHER FINDINGS (OFFSPRING)
Sex ratio:
Sex ratio at birth (as assessed by percentage males) was not influenced by treatment and there was no selective effect on pup survival of either sex.

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

ca. 10 000 ppm

Based on:

test mat.

Sex:

male/female

Results: F2 generation

Effect levels (F2)

Dose descriptor:

NOEL

Generation:

F2

Effect level:

ca. 10 000 ppm

Based on:

test mat.

Sex:

male/female

Overall reproductive toxicity

Reproductive effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

It was concluded that D911P had no adverse effects upon fertility or reproductive performance when rats were exposed to diets containing up to 10000 ppm of the test material through two successive generations. D911P fed through two generations had no adverse effect on the seminology parameters investigated and no histopathological effects on the reproductive organs.

Executive summary:

The influence of D911P on the fertility and reproductive capacity of two successive generations was assessed in male and female rats. The substance was administered continuously in the diet at concentrations of 1000, 5000 or 10000 ppm to groups of rats throughout the two generations. The highest dosage group animals were given 20000 ppm of D911P for approximately six weeks (43 days) at the start of the Fo generation but this was reduced to 10000 ppm because of a marked reduction in bodyweight gain of the males. D911P had no adverse effects upon fertility or reproductive performance when rats were exposed to diets containing up to 10000 ppm of the test material through two successive generations. D911P fed through two generations had no adverse effect on the seminology parameters investigated and no histopathological effects on the reproductive organs.