Alterations in polyamines and nucleic acids in the rat ventral prostate during cyproterone acetate treatment and subsequent withdrawal

Abstract

The effect of cyproterone acetate (CA) was examined on polyamines and nucleic acid levels of the ventral prostate at various time intervals after daily administration of this antiandrogen (1.25 mg/100 g, sc) to adult rats. While CA markedly reduced prostatic spermine, spermidine, and putrescine levels after 10 days of treatment, changes in the latter two polyamines appeared to be biphasic with significant elevations being observed at day 1, followed by marked decreases that were evident as early as the 3rd day. Cessation of antiandrogen treatment for 10 days in rats that had been pretreated with CA significantly elevated prostatic spermine levels, while the concentration of spermidine and putrescine remained slightly lower than controls. In contrast, CA failed to exert any marked effect on prostatic spermine and putrescine levels when animals were treated concomitantly with testosterone (5 mg/100 g per day, sc; 10 days). Like prostatic spermidine and putrescine, RNA levels and the RNA:DNA ratio were significantly elevated 24 h after CA administration, but decreased thereafter to levels markedly lower than controls by the 10th day of treatment. DNA concentration was increased slightly during CA administration, although the total content of this nucleic acid remained unaltered. While cessation of CA administration restored RNA and the RNA:DNA ratio to control values, these were significantly increased in rats given both CA and testosterone. Results of the present investigation support the hypothesis that changes in cellular polyamines may be related to alterations in RNA metabolism, and thus cellular differentiation of the prostate gland following androgenic deprivation and (or) depletion.