Potentiating effect of buserelin acetate, an LHRH agonist, on the proliferation of ventral prostatic epithelial cells in testosterone-treated castrated rats.BACKGROUND:We used buserelin acetate ([D-Ser(But)6] LHRH ), an LHRH agonist and strong blocker of LH secretion, as a treatment for prostatic cancer. It is possible that this LHRH agonist has a proliferative effect on the prostate in addition to suppressing LH secretion. The purpose of this study was to examine the proliferative effect of LHRH agonist on rat prostatic epithelial cells.METHODS:We determined the optimal dose of testosterone necessary to maintain a positive level of proliferating cell nuclear antigen (PCNA) in the ventral prostatic epithelial cells of castrated Wistar rats. Testosterone-treated rats then received various doses of buserelin acetate. Castrated rats without exogenous testosterone also received buserelin acetate. The PCNA positivity was determined by immunohistochemistry with anti-PCNA monoclonal antibody.RESULTS:The optimal dose of testosterone enanthate was 4 mg at 0 and 28 days after castration. Administration of buserelin acetate on day 0 and 28 in doses of 0.16 mg to 1.28 mg significantly increased PCNA positivity in a dose-dependent manner. Administration of buserelin acetate to castrated rats without testosterone also increased PCNA positivity but there was no statistical significance.CONCLUSIONS:Buserelin acetate has a potentiating effect on the proliferation of ventral prostatic epithelial cells of castrated rat in the presence of a physiological level of exogenous testosterone. This effect may slightly influence the result of hormonal therapy by LHRH agonist.