Antifertility effects of estradiol in adult male rats

The dose-related effects of estradiol 17-beta at the doses 0.1 mug, 10 mug, 100 mug, 200 mug, 300 mug, 400 mug, 1000 mug/kg/day were determined on spe rm motility, potency, fertility parameters, serum levels of LH, FSH, PRL an d testosterone, weights of testes and accessory sex organs, weights of pitu itary and adrenal glands. The drug was administered daily via sc route for a period of 60 days. Dose-related effects on fertility parameters of the es tradiol-treated male rats were ascertained by allowing them to mate With no rmal cycling female rats. Estradiol at 0.1 mug/kg/day dose significantly re duced sperm motility with no effects seen on potency or fecundity, serum LH , FSH, PRL or testosterone, weights of testes and accessory sex organs whil e pituitary weight increased. Estradiol at 10 mug/kg/day dose significantly reduced motility, serum LH, FSH, weights of testes and accessory sex organ s, while pituitary weight increased with no effects seen on potency, fecund ity, PRL or testosterone. Estradiol at 100-1000 mug/kg/day dose significant ly reduced motility, potency and fecundity, serum LH, FSH and testosterone, weights of testes and accessory sex organs while serum PRL and the weights of pituitary and adrenal glands increased significantly. Histology of the testes revealed disorganization of the cytoarchitecture in the seminiferous tubules, vacuolation, absence of lumen and compartmentalization of spermat ogenesis. Estradiol withdrawal, testosterone propionate at 100 mug/kg/day o r antiestrogen (tamoxifen citrate) at 400 mug/kg/day prevented the histolog ical changes. It is concluded that estradiol reduces sperm motility even at a low dose. Low doses (<10 <mu>g/kg/ day) appear to maintain whilst high d oses (>10 mug/kg/day) reversibly disrupt spermatogenesis. Prevention of dis ruption by testosterone or antiestrogen indicates crosstalk between androge n and estrogen receptors in Sertoli cells. Loss of potency and fecundity al so suggests effects on crosstalk between these receptors in other male repr oductive organs. (J. Endocrinol. Invest. 24: 598-607, 2001) (C) 2001, Editr ice Kurtis.