Abstract
To clarify the restoration from inhibition of the gonad induced by hexestroldicaprylate (H.), adult male rats were injected subcutaneously with a single dose of 400 pg/0.2 mZ of H. in oil, and autopsied 3, 6, 12 and 24 weeks after the injection. In the reproduc-tive organs an atrophic tendency was observed clearly 3 weeks, a maximal decrease inweight 6 weeks, and a tendency to recover in weight 12 weeks after the injection. Thesperm concentration decreased obviously in all the rats 3 weeks after the injection. Nosperms were found in the majority of the rats 6 weeks after the injection. The spermato-genetic function was recovered to almost the same level as that of untreated control ratsby 24 weeks after the injection. The recovery of fertilizing ability of those rats was con-firmed 29 weeks after the injection, when all the rats successfully mated with normal adultfemales, which became pregnant. II. was a weak synthetic estrogen, as proved by thevaginal estrous test on spayed female rats. It was revealed, however, that injection witha single dose of H. could inhibit spermatogenesis in adult male rats for a long time with-out inducing any macroscopic side effect, and that spermatogenesis was restored 6 to 7months after the injection.
