Involvement of prostate in the regulation of serum levels of FSH, LH, and prolactin in male rats.

Circulatory levels of LH and FSH were measured in serum of male rats (28, 35, 42, 63, 70, 77, and 207 days of age) 7 days following sham operation, castration (C), prostatectomy (P), and castration + prostatectomy (C + P). In C + P rats that were 49, 63, 70, 77, and 207 days of age, the plasma FSH was significantly elevated as compared to the C group. Administration of aqueous prostatic extract restored the circulatory FSH level in C + P animals to that observed in C animals, whereas in C animals FSH levels were suppressed, indicating inhibinlike activity. In rats 49 and 77 days of age, circulatory LH levels were significantly suppressed in C + P animals as compared to the C group. Both castration and prostatectomy alone suppressed circulatory prolactin levels. Administration of prostatic extract to castrated animals restored the prolactin levels to that of the sham-operated control animals. Results of the present study suggest a role of the prostate in feedback regulation of FSH and prolactin.