The induction of polycystic ovaries in mature cycling rats by the administration of dehydroepiandrosterone (DHA)

Abstract

The chronic administration of various doses of dehydroepiandrosterone (DHA: 1.5, 3, 4.5 and 6 mg/100 g BW: 20 days) to mature cycling rats will interrupt the estrous cycle, as illustrated by a constant estrus vaginal smear present more than 84% of the treatment time and will induce polycystic ovaries. An analysis of gonadotropins after chronic DHA treatment (6 mg/100 g BW) revealed slightly increased FSH, elevated prolactin and depressed serum LH levels. The biological activity of various doses of DHA was assessed by determining their effectiveness to suppress the castration hypersecretion of gonadotropins. Two sets of experiments were undertaken: mature animals were castrated and 15 days later administered DHA for 20 days or DHA was administered for 20 days immediately after castration. The immediate replacement of DHA was much more effective in suppressing the hypersecretion of gonadotropins. The 3 mg/100 g BW dose of DHA was the lowest, most effective dose in preventing the postcastration rise in serum gonadotropins and was selected for further experimentation. When 3 mg/100 g BW of DHA was administered for short term durations, polycystic ovaries and changes in gonadotropins occurred after 3 days of treatment and continued through 15 days of treatment. During the 15 day treatment with the 3 mg dose of DHA, typical changes in the pattern of FSH, LH and prolactin occurred that were similar to those reported with the 6 mg dose. There were no differences in individual gonadotropin values between the 3 and 6 mg dose.