Vaginal cyclicity, sexual receptivity, and eating behavior of the female rat following treatment with chlordecone

Stanozolol, oxymetholone, and testosterone cypionate effects on the rat estrous cycle

Anabolic-androgenic steroid (AAS) effects on the estrous cycle of adult Long-Evans rats were examined in four different experiments. Sexual receptivity, vaginal cytology, and body weight were monitored throughout two-week baseline, AAS treatment, and recovery periods. In Experiments 1-3, rats were administered stanozolol, oxymetholone, or testosterone cypionate within dose ranges selected to mimic the human abuse levels of each compound. In these studies, the highest doses of stanozolol (5 mg/kg), oxymetholone (12 mg/kg), or testosterone cypionate (7.5 mg/kg) disrupted the cyclical display of sexual receptivity and vaginal estrus. To compare effects on estrous cyclicity across AAS compounds, rats in Experiment 4 received a single dose (7.5 mg/kg) of each compound for 2 weeks. At the 7.5 mg/kg dose, all AAS compounds interfered with the cyclical display of vaginal estrus, although effects on sexual receptivity were not uniform. No striking AAS effects on body weight were seen in any experiment. The short-term administration of AAS compounds at high doses disrupts female neuroendocrine function in rats.

The effects of 17 alpha-methyltestosterone, methandrostenolone, and nandrolone decanoate on the rat estrous cycle

In a series of four separate experiments, the effects of anabolic-androgenic steroid (AAS) compounds on the estrous cycle of adult Long-Evans rats were examined. Sexual receptivity, vaginal cytology, and body weight were monitored throughout a 2-week baseline, AAS treatment, and recovery periods. In Experiments 1-3, subjects were administered 17 alpha-methyltestosterone, methandrostenolone, or nandrolone decanoate at doses selected to mimic the human abuse levels of each compound. In these studies, the highest doses of 17 alpha-methyltestosterone (7.5 mg/kg) and nandrolone decanoate (5.6 mg/kg) disrupted behavioral and vaginal cyclicity, whereas the highest dose of methandrostenolone (3.75 mg/kg) appeared to have slightly less robust effects. To compare effects on estrous cyclicity across AAS compounds, subjects in Experiment 4 received a single high dose (7.5 mg/kg) of each compound for 2 weeks. At this dose, all AAS compounds interfered with vaginal cyclicity, although effects on behavioral cyclicity and uterine weight were not uniform. Across all 4 experiments, AAS effects on body weight were minimal. The short-term administration of AAS compounds at levels commonly used by humans disrupts female neuroendocrine function in a dose-dependent manner.

Inhibition of ovarian compensatory hypertrophy by the administration of methyl parathion in hemicastrated albino rats

Methyl parathion, an organophosphorus pesticide that is a potent acetylcholinesterase inhibitor in animals, was administered IP in graded doses from 2.5 to 5.0 mg/kg body weight to normal hemicastrated virgin rats for 15 consecutive days. Sham-operated and hemicastrated control groups were treated with a similar quantity of olive oil vehicle. The vaginal smears and body weights of treated and control groups were recorded daily and rats were sacrificed on the 16th day. The ovaries, adrenals, liver, kidney, and uterus were removed and weighed, and the ovary from each animal was serially sectioned and stained for histologic studies. The hemicastrated control group revealed a significant increase in ovarian weight with 45% hypertrophy and a significant increase of total healthy and atretic follicles when compared with sham-operated control rats. Treatment with 2.5 and 3.5 mg methyl parathion revealed no change in the ovarian weight with 48 and 42% hypertrophy, respectively, and no change in healthy and atretic follicles when compared with hemicastrated oil-treated controls. However, treatment with 4.0 and 5.0 mg methyl parathion resulted in a significant decrease in ovarian weight gain with 13 and 8% hypertrophy, respectively, a significant decrease in the number of healthy follicles, and no change in the atretic follicles. The number of estrous cycles and duration of each estrous cycle were affected significantly with 3.5, 4.0, and 5.0 mg methyl parathion treatment when compared with controls. There were no significant changes in adrenal, liver, kidney, or uterine weight in the methyl parathion-treated groups except a decrease in uterine weight with 5.0 mg treatment when compared with oil-treated hemicastrated controls.

ATSDR evaluation of health effects of chemicals. II. Mirex and chlordecone: health effects, toxicokinetics, human exposure, and environmental fate

This document provides public health officials, physicians, toxicologists, and other interested individuals and groups with an overall perspective of the toxicology of mirex and chlordecone. It contains descriptions and evaluations of toxicological studies and epidemiological investigations and provides conclusions, where possible, on the relevance of toxicity and toxicokinetic data to public health. Additional substances will be profiled in a series of manuscripts to follow.

Lindane does not alter the estrogen receptor or the estrogen-dependent induction of progesterone receptors in sexually immature or ovariectomized adult rats

Lindane, gamma-1,2,3,4,5,6-hexachlorocyclohexane (gamma-HCH), has been shown to disrupt reproductive function in mammals. Many of these adverse effects on female reproduction such as alterations in sexual receptivity, disrupted ovarian cyclicity, reduction in uterine weight and termination of pregnancy are thought to be due to altered ovarian hormone secretions and/or an impaired response to circulating estrogen. It has been suggested that gamma-HCH may block the response of estrogen-dependent tissues to estradiol via an interaction with the estrogen receptor. To test this hypothesis, estrogen (ER) and progesterone (PR) receptor affinity and number were evaluated in sexually immature, 17 beta-estradiol-3-benzoate (EB)-primed Long Evans female rats following exposure to vehicle or gamma-HCH (40 mg/kg) for 7 days (Study 1) and in adult, ovariectomized EB-primed Long-Evans rats following gavage with vehicle or gamma-HCH (0, 10, 20, or 40 mg/kg) for 5 days (Study 2). Chlordecone (kepone; 40 mg/kg; i.p.) was used in Study 2 as a positive control for the alteration of the estrogen-induction of PR in the pituitary. Neither gamma-HCH nor chlordecone altered serum estradiol concentrations. gamma-HCH did not change the ER number (1, 24, or 30 h after EB) or the estrogen-dependent induction of PR (24 or 48 h after EB) in the hypothalamus (HYP), pituitary, or uterus. These data indicate that the effects of gamma-HCH on the female reproductive system do not involve an alteration in the ER and that heterogeneity exists between target tissues in their response to xenobiotics.