Effects of metyrapone on reproductive organs of house mice (38533).

The effects of chronic administration of metyrapone, a specific adrenal 11beta-hydroxylase inhibitor, were examined on the reproductive organs of house mice. In one experiment, immature (30 days old) mice of both sexes received daily injections of either metyrapone (100 mg/kg) or saline ip for 30 days. In a second experiment, mature mice (90 days old) were treated in like manner either with metyrapone (100 mg/kg) or saline for 21 days. Twenty-four hours after the last injection, mice were killed, fixed in formalin, and organs were weighed and examined by light microscopy. There was significant impairment of ovarian and uterine development in the young female metyrapone-treated mice with the incidence of corpora lutea being reduced 82%. Seminal vesicle and body weights were significantly reduced in juvenile males. Among mature animals, a 14% decrease in adrenal gland weight from adult females was the only signigicant effect of prolonged treatment with metyrapone. These data support the hypothesis that increases in pituitary-adrenocortical function may impair development of reproductive organs in small rodents.