The effect of testosterone and other adrenal steroids on PMS-induced ovulation in the immature rat.

17 alpha-hydroxyprogesterone (up to 200 mug/day) and 11 beta-hydroxyandrostenedione (up to 500 mug) had no effect on PMS-induced ovulation in intact immature rats. 10 mug/day of testosterone propoinate (TP) on days 28-30 of life decreased the percent of animals ovulating and the number of ova produced; this effect persisted in adrenalectomized animals with or without corticosterone replacement. Three daily doses of 10 mug TP increased the electrical threshold of the medial preoptic area in pentobarbital-blocked, PMS-stimulated animals. And TP decreased the rate of release and synthesis of FSH during the ovulatory surge, and the storage and rate of release of LH; it also inhibited the response to HCG in the PMS-primed animal, suggesting a direct target-organ effect.