Expression of glutathione-peroxidase (GSH-PO) in the rat ventral prostate--effect of castration and administration of testosterone.

Immunolocalization of glutathione-peroxidase (GSH-PO), apoptosis and bcl-2 protein in the rat ventral prostate was investigated in the presence or absence of androgen. Male Sprague-Dawley rats were divided into four experimental groups. Group 1 consisted of intact controls. In group 2, rats were sacrificed two days after castration. In groups 3 and 4, rats were administered subcutaneously 1 mg/animal of testosterone-propionate daily for three or seven days at two days after castration. The intensity of GSH-PO staining in the glandular epithelial cells of the ventral prostate was remarkably decreased after castration (Group 2), and it clearly recovered when testosterone was administered (Groups 3 and 4) to the castrated rats. The prostatic GSH-PO mRNA levels were diminished in the castrated rat ventral prostate but greatly increased by testosterone (Groups 3 and 4). Furthermore, castration (Group 2) induced apoptosis in the prostatic glandular epithelial calls and the apoptosis was reduced by testosterone-administration (Groups 3 and 4) to the castrated rats. In groups 3 and 4, expression of bcl-2 protein was clearly detected in the glandular epithelial cells of the ventral prostate. These findings strongly suggested that expression of GSH-PO and bcl-2 protein in the glandular epithelial cells of the rat ventral prostate is testosterone-dependent.