Altered sensitivity of uterus to progesterone-estradiol in rats treated neonatally with androgen and ovariectomized as adults.

Female rats were made persistent-estrous and anovulatory by giving a single injection of 1.25 mg of testosterone propionate 4 days after birth. The rats were ovariectomized when adult and given 7 daily injections of progesterone plus estradiol in amounts sufficient to condition the uteri fbr fbrmation of deciduomata in response to trauma. The administration of the hormones was commenced on the day following ovariectomy, or 32 or 62 postoperative days after priming with estradiol for 2 days. Incidence of deciduomata following uterine traumatization on the 4th day of the injection period was always much higher in non-androgenized controls than in androgen-sterilized rats. It seems likely that neonatal androgenization results in a permanent or at least a long-lasting reduction of uterine sensitivity to progesterone-estradiol. The longer the interval between ovariectomy and the beginning of progesterone-estradiol administration, the less marked was the mucification of the vaginal epithelium. There was no correlation between the degree of vaginal mucification and the development of deciduomata.