Pp. Parte et al., Effect of 5 alpha-dihydrotestosterone implants on the fertility of male rats treated with tamoxifen, J ANDROLOGY, 21(4), 2000, pp. 525-533
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.