Effect of Castration or Testosterone Treatment on Hypothalamic FSH-RF and Pituitary FSH of Male Rats ∗

Summary

Following castration of adult, male rats there was a decline in hypothalamic FSH-RF, when assayed by an in vitro method, which was apparent within 8 day and persisted for at least 29 days postoperatively. When intact rats were treated with a large dose of testosterone propionate (2 mg/day) for 2 weeks, there was no consistent alternation in the level of stored FSH-RF. Castration and testosterone treatment were associated with alteration in weights of sex accessories, anterior pituitary weight, and FSH concentration. The decline in hypothalamic FSH-RF in castrates, at a time when FSH release is increased above normal levels, was considered to be consistent with the view that enhanced release of FSH-RF may play a role in augmenting FSH release in this condition.