The effects of testosterone, 17beta-hydroxy-5alpha-androstane-3-one (5alpha-dihydrotestosterone; 5alpha-DHT), 5alpha-androstane-3alpha, 17beta-diol (3alpha-androstanediol; 3alpha-diol) and 5alpha-androstane-3beta, 17beta-diol (3beta-androstanediol; 3beta-diol) on the development of fertilizing ability by spermatozoa in the epididymis were compared in castrated hamsters. The left corpus epididymidis was ligated for 14 days in intact and castrated animals to prevent the in-flow of spermatozoa into the cauda epididymidis and the ductuli efferentes were bilaterally ligated. The fertilization rate of spermatozoa in the left cauda epididymidis of control animals decreased to 71.1% after 14 days whereas that of spermatozoa in the unobstructed right cauda epididymis remained at the control level of 100%. After castration, 50 mug testosterone, 25 mug 5alpha-DHT and only 9 mug 3alpha-diol/day were the minimal doses that facilitated normal development of fertilizing ability but 75 mug testosterone, 37.5 mug 5alpha-DHT and 12.5 mug 3alpha-diol/day were required to maintain sperm survival at the control level. However, 3beta-diol was ineffective for both sperm maturation and survival.
Male hamsters of known fertility were injected subcutaneously with \g=a\-chlorohydrin to determine the minimal antifertility dose and to elucidate its site of action. Fertility tests at 4-day intervals showed that \g=a\-chlorohydrin(66 mg/kg) induced infertility within 4 days and fertilization did not occur after artificial insemination with spermatozoa from the cauda epididymidis of such animals. Comparable daily treatment produced the same antifertility effect subsequent to bilateral ligation of the corpus epididymidis and also in castrated animals given daily treatment (100 \g=m\g/day) with either testosterone, 5\g=a\-dihydrotestosterone or 3\g=a\-androstanediol. The infertility was not related to deficiency of androgen, as judged by the concentration of fructose in the seminal vesicles, or to impaired ejaculation.
SUMMARY
Experiments were designed to discover if oestradiol benzoate induces loss of fertilizing ability of hamster epididymal spermatozoa by acting directly on the cauda epididymidis. Spermatozoa were retained in the cauda epididymidis by ligating the distal corpus epididymidis and proximal ductus deferens and fertilizing ability was compared in oestrogen-treated, intact hamsters and in castrated or hypophysectomized animals maintained with testosterone. Fertility tests showed that 12 daily s.c. injections of 3·5 or 5 μg oestradiol benzoate reduced fertilizing ability to 35·2 and 0%, respectively; supplementary testosterone did not prevent the adverse effect of oestrogen and reduced fertilizing ability was shown not to be related to a deficiency of circulating testosterone as judged by fructose concentration in the seminal vesicles. Daily treatment of androgen-maintained castrated or hypophysectomized hamsters with 3·5 μg oestradiol benzoate for 12 days reduced fertilizing ability to 43·7 and 31·3%, respectively. The results suggest that oestradiol benzoate reduces fertilizing ability in hamsters by acting directly on the cauda epididymidis and inhibiting the effect of testosterone.
Summary. Ligation of the distal corpus epididymidis and ductus deferens for 20 days resulted in low fertilizing ability of spermatozoa isolated in the cauda epididymidis of intact hamsters and castrated animals treated daily with 100 \g=m\g testosterone. Following ligation of the ductuli efferentes and vasectomy in intact hamsters, however, new spermatozoa accumulated in the cauda epididymidis and fertilizing ability was maintained at the control level after 20 days. In the testosterone-treated castrated hamsters, the resulting fertilizing ability was dose-dependent: spermatozoa continued to migrate through the epididymis after twenty daily injections of either 12\m=.\5or 100 \g=m\g testosterone but developed fertilizing ability only after treatment with the higher dose of testosterone. The results show that circulating testosterone is important for sperm maturation in the hamster.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.