Influence of pituitary and adrenocortical hormones on prostatic secretion protein, a major protein in rat prostate

Prostatic secretion protein (PSP) is an androgen-sensitive, quantitatively important protein in rat ventral prostate which has been shown to inhibit the nuclear uptake and decrease the DNA-binding capacity of the androgen-receptor complex. In the present study, the influence of the pituitary, adrenals, and gonads on the concentration of PSP in the prostate was studied. Hypophysectomy decreased the concentration of PSP to about 10% of the control level, an effect similar to that obtained by castration. No effects on prostatic wet weight or PSP concentration were observed following substitution of hypophysectomized rats with human growth hormone, rat prolactin, or rat growth hormone. On the other hand, PSP concentration as well as wet weight of the prostate were normalized in hypophysectomized rats after administration of testosterone propionate. These results are in line with a direct extrahypophyseal effect of androgens on the prostate. Adrenalectomy did not affect the concentration of PSP, nor the wet weight of the prostate. Administration of estramustine decreased the wet weight of the prostate but did not affect the prostatic concentration of PSP in normal rats. Combined treatment with testosterone propionate and estramustine seemed to increase both the wet weight and the concentration of PSP more than administration of testosterone propionate alone. These results indicate a synergistic effect between estramustine and testosterone propionate.