The Androgenic Regulation of Abundant mRNA in Rat Ventral Prostate

Abstract

The most abundant poly(A)‐containing RNA accounting for approximately half the total is regulated by testosterone in rat ventral prostate. A complementary DNA probe to these sequences was isolated by hybridizing the total cellular poly(A)‐containing RNA with its complementary DNA to an r o t 1/2 value of 2 × 10 −2 mol l −1 s and separating the abundant cDNA, from the non‐abundant cDNA by hydroxyapatite chromatography. The abundant cDNA, complementary to about three different poly(A)‐containing RNA sequences comprising 45% of the total poly(A)‐containing RNA, has been used to investigate the effect of androgens on their metabolism. Following castration there is a progressive decrease in the abundant sequences from 45% of the total in normal animals to less than 0.03% after 14 days; testosterone administration in vivo results in their regeneration. The sequences were not detected in seminal vesicle, liver, heart or spleen but represented about 0.01% of the poly(A)‐containing RNA of kidney. Translation of the poly(A)‐containing RNA in vitro in a cell‐free system derived from wheat germ resulted in the synthesis of four major proteins which could be separated by polyacrylamide gel electrophoresis. Their synthesis, as measured by [ 35 S]methionine incorporation, accounted for 40 – 50% of the total incorporation and declined after castration but was restored by testosterone treatment. We conclude that a class of àbundant poly(A)‐containing RNA which codes for four major proteins is regulated by testosterone in rat ventral prostate.