Male Wistar rats were hypophysectomized and the effects on spermatogenesis were quantified by stereological techniques. Restoration of normal spermatogenesis was attempted 32 days after hypo-physectomy by treatment with FSH (designated F), LH (L) or testosterone (T) singly or in combina-tion for a further 32 days. In another experiment, maintenance of spermatogenesis was attempted using FSH (F), testosterone (T) or dihydrotestoterone (D). Treatment began two days after hypo-physectomy and was continued for a further 32 days.

Hypophysectomy of the adult male rat depressed the activity of acid phosphatase and acid proteinase, but increased the activity of p-glucuronidase in the testis. Groups of rats were treated with FSH, LH or testosterone alone or in combination after 32 days of post-hypophysectomy regression (restoration experiment) for a further 32 days, or with FSH, testosterone or dihydrotestosterone alone or in combination commencing at 2 days after hypophysectomy (maintenance experiment) for a further 30 days.