Triclocarban

Toxicity to reproduction

Administrative data

Endpoint:

toxicity to reproduction

Remarks:

other: reproductive toxicity study

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from handbook or collection of data.

Data source

Reference

Reference Type:

publication

Title:

Effects of Test chemical on Male Rat: Augmentation of Androgen Action

Author:

Duleba et al.

Year:

2011

Bibliographic source:

Reproductive Sciences 18(2) 119-127

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

A reproductive toxicity study to investigate the effect of the test chemical in Sprague-Dawley rats.

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Triclocarban

EC Number:

202-924-1

EC Name:

Triclocarban

Cas Number:

101-20-2

Molecular formula:

C13H9Cl3N2O

IUPAC Name:

1-(4-chlorophenyl)-3-(3,4-dichlorophenyl)urea

Test material form:

other: Solid

Details on test material:

- Name of test material (as cited in study report): Triclocarban (TCC)
- Molecular formula (if other than submission substance): C13H9Cl3N2O
- Molecular weight (if other than submission substance): 315.58 g/mol
- Substance type: Organic
- Physical state:
- Purity: 99.3%
- Impurities (identity and concentrations): 0.7% (identity of impurities unknown)
- Analytical purity: 99.3%
- Impurities (identity and concentrations): 0.7% (identity of impurities unknown)
- Composition of test material, percentage of components:NA
- Purity test date:NA
- Lot/batch No.:NA
- Expiration date of the lot/batch:NA
- Isomers composition:NA
- Other:NA

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male

Details on test animals or test system and environmental conditions:

Details on test animal

TEST ANIMALS
- Source: No data available
- Age at study initiation: 48-52 days
- Weight at study initiation: 223.2±14.9 to 226.7±20.9
- Fasting period before study: No data available
- Housing: No data available
- Diet (e.g. ad libitum): Standard rat chow
- Water (e.g. ad libitum): No data available
- Acclimtization period: No data available

ENVIRONMENTAL CONDITIONS
- Temperature (°C): No data available
- Humidity (%):No data available
- Air changes (per hr): No data available
- Photoperiod (hrs dark / hrs light): No data available

Administration / exposure

Route of administration:

oral: feed

Type of inhalation exposure (if applicable):

not specified

Vehicle:

other: Standard rat chow

Details on exposure:

Details on exposure
PREPARATION OF DOSING SOLUTIONS: No data available

DIET PREPARATION
- Rate of preparation of diet (frequency): No data available
- Mixing appropriate amounts with (Type of food): Standard rat chow
- Storage temperature of food: No data available

VEHICLE
- Justification for use and choice of vehicle (if other than water): Standard rat chow
- Concentration in vehicle: 0 or 0.25% per day
- Amount of vehicle (if gavage): No data available
- Lot/batch no. (if required): No data available
- Purity: No data available

Details on mating procedure:

- M/F ratio per cage: Not available
- Length of cohabitation: Not available
- Proof of pregnancy: [vaginal plug / sperm in vaginal smear] referred to as [day 0 / day 1] of pregnancy Not available
- After … days of unsuccessful pairing replacement of first male by another male with proven fertility. Not available
- Further matings after two unsuccessful attempts: [no / yes (explain)] Not available
- After successful mating each pregnant female was caged (how): Not available
- Any other deviations from standard protocol: Not available

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

No Data

Duration of treatment / exposure:

10 days

Frequency of treatment:

Daily

Details on study schedule:

No data available

Doses / concentrations

Remarks:

Doses / Concentrations:
0 or 0.25% per day
Basis:
nominal in diet

No. of animals per sex per dose:

Control: 12 animals
0.25% per day: 12 animals

Control animals:

yes, concurrent vehicle

Details on study design:

No of animals: Twenty-four Sprague-Dawley rats
Details of controls: 12 rats
- Dose selection rationale: The dose of the test chemical was based on our previous in vitro work and previous study evaluating effects of oral exposure to the test chemical in castrated animals.
- Rationale for animal assignment (if not random): Twenty-four Sprague-Dawley rats (at the age of 48-52 days) were randomly assigned to 2 treatment groups, each consisting of 12 animals: control group (standard diet) and the test chemical group (0.25% TCC by weight in diet of standard rat chow).
- Fasting period before blood sampling for clinical biochemistry: No Data Available
- Other: No Data Available

Positive control:

No data

Examinations

Parental animals: Observations and examinations:

Blood was collected by cardiac puncture prior to euthanasia.

Oestrous cyclicity (parental animals):

No data available

Sperm parameters (parental animals):

No data available

Litter observations:

No data available

Postmortem examinations (parental animals):

Liver, kidney, adrenal glands, testes, levator ani-bulbocavernosus muscle (LABC), glans penis, ventral prostate, and seminal vesicles were surgically removed and weighed.

Organs of half of the animals from each group were fixed and assessed histologically. Organs of the other half of the animals were freeze-dried, weighed, and protein and DNA content determined.

Histoloy and Immunohistochemicstry Protein and DNA determinations were performed, and in the serum levels of luteinizing hormone was measured and a T assay was conducted. From the serum the detection and quantification of TCC was also measured and recorded.

Postmortem examinations (offspring):

No data available

Statistics:

All data were expressed as mean+SE. Data were analyzed, as appropriate, either by Student t test or, in the absence of normal distribution, by Wilcoxon rank-sum test using JMP statistical package for Macintosh computer.

Reproductive indices:

No data available

Offspring viability indices:

No data available

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

not specified

Dermal irritation (if dermal study):

not specified

Mortality:

not specified

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Pretreatment body weights were comparable in both groups; however, during the 10-day course of the study, animals exposed to the treatment gained significantly more weight than control animals (on average, 85.6 vs 67.0 g). This resulted in an average 5.1% greater terminal weight in the treatment group.

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

There were no visible abnormalities of any of the accessory sex glands, penis or testes, in treated animals and no histologically distinguishable difference between specimens from the control and treated animals. The vesicular glands were variably distended with fluid, the epithelium was simple or pseudostratified and thrown into numerous, complex, primary and secondary folds extending into and sometimes obliterating the lumen. Lobes were surrounded by connective tissue and a thick layer of smooth muscle but appeared similar in treated and control tissues. The acini of the prostate gland were also distended, lined by a simple epithelium, and surrounded by a thin connective tissue and smooth muscle layer.

Histopathological findings: neoplastic:

not specified

Other effects:

no effects observed

Description (incidence and severity):

Lutenizing Hormones: No significant differences in either of circulating LH were noted between treated and control groups.
Effect of the test chemical on Androgen Induced Transcriptional Activity in Human Prostate Cell: Testosterone and DHT treatments induced luciferase activity in LNCaP cells transfected with probasin or simple ARE promoters. Cotreatment of androgen with the test chemical (1.0 nmol/L) further increased luciferase activity by 221% (Probasin promoter) and 175% (ARE promoter) in LNCaP cells compared to androgen treatment alone (P < .01,). Similarly, in C4–2B cells, the test chemical further potentiated androgen-induced luciferase activity by 25.9% (Probasin promoter) and 38.5% (ARE promoter), compared to androgen treatment alone, although the amplification was less substantial than that observed in LNCaP cells, which have higher expression of AR (P < .05). In both cell lines, the amplification enhanced by the test chemical was significantly suppressed by the strong AR binding inhibitor, bicalutamide.

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not specified

Reproductive function: sperm measures:

not specified

Reproductive performance:

not specified

Effect levels (P0)

Dose descriptor:

LOAEL

Effect level:

250 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Increased body weight and organ enlargement.

Remarks on result:

other: Not Specified

Target system / organ toxicity (P0)

Critical effects observed:

yes

Lowest effective dose / conc.:

2 500 ppm

System:

male reproductive system

Organ:

Levatorani plus bulbocavernous muscle complex

seminal vesicle

seminiferous tubules

testes

ventral prostate gland

Treatment related:

no

Dose response relationship:

no

Relevant for humans:

not specified

Results: F1 generation

General toxicity (F1)

Sexual maturation:

not specified

Effect levels (F1)

Remarks on result:

not measured/tested

Overall reproductive toxicity

Reproductive effects observed:

not specified

Treatment related:

not specified

Applicant's summary and conclusion

Conclusions:

Based on all the observations and conclusions, the LOAEL was considered to be 0.25% per day i.e. 250 mg/kg /day when male rats were exposed to test chemical.

Executive summary:

In a reproductive toxicity study, the effect of the test chemical was evaluated in male Sprague-Dawley rats for 10 days. The seven-week-old male Sprague-Dawley rats received either a normal diet or a diet supplemented with the test chemical (0.25% in diet). No mortalities were observed in the males. All organs were weighed at time of sacrifice before being subjected to microscopic examination or analysis for protein and DNA contents. Terminal mean body weight was 5.1% higher in the treated group compared to the control group. Food intake was not measured. Absolute liver weight was significantly increased in the 2500 ppm treatment group compared to the control group. No statistically significant differences in absolute organ weights were observed for the kidneys, adrenal glands or testes. Accessory sex organs were significantly enlarged in the 2500 ppm treatment group, with seminal vesicles weighing 42% more, ventral prostate 37% more, LABC 136% more, and glans penis 35% more. Protein and DNA contents in ventral prostrate, LABC muscle and glans penis were significantly elevated in the 2500 ppm treatment group. There were no gross abnormalities of any of the accessory sex glands, testes or penis among the treated animals. Histologically, all tissues appeared normal and there were no consistent histological differences between the two groups.