Effect of 5 alpha-dihydrotestosterone implants on the fertility of male rats treated with tamoxifen

In adult male rats, tamoxifen (TAM) reduces circulating levels of luteinizi ng hormone (LH) and testosterone (T) with no effect on follicle-stimulating hormone (FSH) and prolactin (PRL). It reduces the male rat's ability to in seminate the female (potency), as well as its siring ability (fecundity). T he objective of the present study was to test whether androgen supplementat ion could reverse all or some of the observed effects of TAM. To obviate th e effects of estrogen, the study was designed to evaluate the beneficial or deleterious effect of 5 alpha-dihydrotestosterone (DHT), a 5 alpha-reduced , nonaromatizable metabolite of T, on the reproductive functions of TAM-tre ated adult male rats. Adult male rats received either saline or TAM (0.2 or 0.4 mg per day PO) for 90 days. A group of TAM-treated rats was implanted with 6 mg DHT from day 50 to day 90. A third group of untreated animals was implanted with 0-, 1-, 3-, or 6-mg DHT implants for 90 days. Mating studie s were done to assess the fecundity, potency, and fertility index at the en d of the treatment. Weights of testes, pituitary, and accessory sex organs were recorded, and circulating levels of LH, FSH, PRL, T, and 17-beta-estra diol were estimated. DHT did not affect the fecundity or fertility index. T AM reduced fecundity, potency, and the fertility index. DHT implants improv ed the fertilizing ability of the TAM-treated male rat. This study discusse s and reviews the role of T and 17-beta-estradiol in sperm-fertilizing pote ntial in light of these observations.