The Uptake and Subcellular Distribution of C14-Labeled Steroid in Rat Ventral Prostate Followingin vivoAdministration of Testosterone-4-C14*

Abstract

Testosterone-4-C14 was administered to rats and the uptake, metabolism and intracellular distribution of radioactivity in ventral prostate was studied. The uptake by several other tissues was also studied. The mean ratio of the total radioactivity found in ventral prostate to that found in blood was 1.13+0.15; whereas, the concentration of chloroform-soluble radioactivity in ventral prostate was double that in blood. Seminal vesicle also had a high level of radioactivity and secreted C14-labeled substances into the seminal fluid. The highest concentration of radioactivity was found in kidney and liver however. The radioactivity of the ventral prostate was largely chloroform-soluble and appeared to consist entirely of A4-androstene- 3,17-dione. This steroid was associated both with RNA-containing particles and the high speed supernatant fraction. While a fairly large amount of radioactivity in blood was chloroform-insoluble conjugated material, only a very litle of this material was found in ventral prostate. It is concluded that the free steroid is both oxidized and concentrated in the prostatic cells and that these cells are relatively impermeable to conjugated testosterone metabolites. Since muscle does not show either the high concentrating or oxidizing effects, it is postulated that these may be related to the hormonal action of testosterone.