Androgenic regulation of poly(A)-containing RNA sequences in rat ventral prostate

Prostate gland: structure, functions and regulation

The prostate gland plays an important role in male reproduction. It secretes enzymes, lipids, amines and metal ions essential for the normal function of spermatozoa. Development, differentiation and maintenance of the prostate gland depend on steroid and peptide hormones. Beside hormones growth factors also regulate the prostate gland. This review will focus on the structure, functions and mode of regulation of the prostate gland.

Androgenic control of polysomal poly(A)-containing RNA in the cultured rat ventral prostate

Testosterone stimulated, at the concentration of 10-7 M and independently of other hormones, the accumulation of polysomal poly(A)-containing RNA (mRNA) in cultured explants of rat ventral prostate and concomitantly also protein synthesis. The hormone-induced accumulation of polysomal mRNA, which reached its maximum at 24 h after testosterone addition, paralleled the preferential labeling of high molecular weight RNA demonstrable with the electrophoretic analysis of the double-isotope labeled RNA after a short pulse (30 min). These findings are consistent with the idea that testosterone activated the synthesis of precursor mRNA leading to an increased amount of polysomal mRNA and eventually an activated protein synthesis. The synthesis and maturation of rRNA appeared to proceed even in the absence of testosterone, which is in contrast to the vivo findings on castrated rats. This partial uncoupling of RNA synthesis from androgenic control may account for the slow and less marked hormonal responses found in protein synthesis and glucose metabolism in cultured explants from normal animals. Because of the lack of uniformity in the suture, routine light microscopic control to assess the viability of cultured explants was found to be a prerequisite for successful biochemical work on prostate culture.

In vitro translation of major abundant class poly(A+)-mRNA from rat seminal vesicle

Total poly (A)-containing messenger RNA [poly(A)-mRNAT] was isolated from seminal vesicles of adult male rats. By preparative 5%-20% linear sucrose gradient centrifugation in 1% SDS, a single peak was seen in the 11S region [poly(A)-mRNA11S]. Poly (A)-mRNAT and poly(A)-mRNA11S were translated in the wheat germ S-30 in vitro translation system. Laemmli-SDS-polyacrylamide slab gel electrophoresis of translation products of poly(A)-mRNAT revealed three major protein bands at approximately 18,500, 15,000, and 14,000 daltons. In vitro translation of poly(A)-mRNA11S across the 11S peak revealed partial purification of the mRNAs for the three predominant proteins. The lower molecular weight part of the 11S peak enriched for the mRNAs coding for the 15,000 and 14,000 dalton polypeptides, and the higher molecular weight side of the peak enriched for the 18,500 dalton mRNA. The highly abundant class of mRNA from rat seminal vesicle can be purified with one sucrose gradient centrifugation.