Active Principle of Swine Prostate Extract: II. Effect of a Peptide Isolated from Swine Prostate Extract on Rat Prostate

Abstract

Previously, we purified a substance from swine prostate extract (PE) that had been reported to have therapeutic effect on benign prostatic hypertrophy. The purified substance (PPE) suppressed ³H-testosterone uptake into the prostate in castrated rats. The present study was carried out to examine the effect of PPE on the weight of accessory sexual organs including the prostate and biochemical parameters in the prostate of normal and/or castrated and testosterone-treated rats. 1) In normal rats, the p.o. administration of PPE daily for a total of 30 days did not affect the prostate weight, but reduced the citric acid content in the prostate. The treatment had little or no influence tissue O₂ uptake, aconitase activity or isocitrate dehydrogenase activity in the prostate. 2) In castrated and testosterone-treated rats, the p.o. treatment with PPE for 15 or 30 days reduced the weight of the prostate as well as the total citric acid, DNA and RNA contents in prostatic tissue. However, these biochemical parameters per tissue weight were not obviously affected except for the citric acid content. These findings suggest that PPE is one of the active principals of PE for the therapeutic efficiency on benign prostatic hypertrophy, probably due to its suppressive effect on excessive uptake of androgen by the prostate.