REGULATION OF PROSTATIC GLUTATHIONE-PEROXIDASE (GSH-PO) IN RATS TREATED WITH A COMBINATION OF TESTOSTERONE AND 17β-ESTRADIOL

Abstract

In order to confirm the relationship between sex hormone administration and glutathione-peroxidase (GSH-PO) in the rat ventral prostate, the levels of GSH-PO mRNA, GSH-PO activity, and lipid peroxide (TBA) value in the ventral prostate were investigated. Male Crj:CD(SD)IGS rats were divided into six 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 subcutaneously administered 1 mg/animal of testosterone daily for three or seven days after two days of castration, respectively. In groups 5 and 6, rats were subcutaneously administered 1 mg/animal of testosterone plus 0.01 mg/animal of 17β-estradiol (E₂) daily for three or seven days after two days of castration, respectively. GSH-PO activity of the ventral prostate homogenate for testosterone or testosterone plus E₂ administration to the castrated rat was increased and the TBA value was remarkably decreased. The prostatic GSH-PO mRNA level was diminished in the castrated rat ventral prostate, but was increased by testosterone or testosterone plus E₂ administration. In particular, the GSH-PO mRNA level of testosterone plus E₂-treated animals was higher than that of testosterone-treated animals. These findings strongly suggest that expression of GSH-PO in the rat ventral prostate is considered to be testosterone- or E₂-dependent. Furthermore, it is suggested that the transcription of prostatic GSH-PO mRNA was regulated by testosterone or E₂ and de novo synthesis of GSH-PO would thus be regulated at transcription level by testosterone or E₂.