Localization of the Biochemical Site of Action of Testosterone on Protein Synthesis in the Seminal Vesicle of the Rat*

Abstract

Although the administration of testosterone clearly causes marked diminution in nitrogen excretion (3) and results in increased protein deposition in kidney, liver, muscle, carcass, and accessory sex tissue (4), the mechanisms of this protein anabolic action are unexplained. While this effect of testosterone is probably the result of an enhancement of protein synthesis, previous attempts to elucidate this action have been complicated by two factors: first, the major enzymatic steps in the synthesis of protein have been described only in the past few years (5); and second, previous attempts to demonstrate an influence of testosterone on protein synthesis in several nonsexual tissues of the rat (6) and mouse (7, 8) have yielded differences which, although consistent, are very small.Several observations have suggested that the rat accessory sex organs might serve as suitable tissues for an exploration of the mechanisms by which testosterone influences protein metabolism. The accessory sex organs are very responsive to the administration of testosterone (9), and in fact, Scow has reported that as much as 25 per cent of the total weight gain induced by testosterone in castrated rats occurs in the sexual tissue (10). Furthermore, Greer has demonstrated that the rat prostate rapidly and selectively concentrates testosterone-4-C14 (11).The present report describes a study of the influence of testosterone administration on protein synthesis in the rat seminal vesicle. Evidence is presented that testosterone administration will en-* This work was presented at the meeting of the Society for Clinical Investigation, May 1, 1961, and has been published in abstract form (1,2 Incubation procedure. Male rats of the Long-Evans strain, weighing from 50 to 75 g, were given, intramuscularly, 5 mg per day of testosterone propionate for periods varying from 12 hours to 3 days. In some experiments the rats were castrated under ether anesthesia at the beginning of the injections. The testosterone-treated animals and either normal or castrated controls were decapitated, and their prostates and seminal vesicles quickly excised and placed in ice-cold Krebs-Ringer bicarbonate buffer, pH 7.4. Slices, approximately 0.5 mm thick, were prepared by hand; the slices from several animals were pooled, washed gently in the ice-cold buffer, blotted, and weighed. Portions of the slices (10 to 100 mg) were placed in centrifuge tubes, and substrates and Krebs-Ringer bicarbonate buffer were added to give a constant volume; samples were incubated either in duplicate or triplicate. The tubes were gassed with 95 per cent oxygen-5 per cent carbon dioxide for 10 seconds, sealed, and incubated at a 30°angle in a Dubnoff metabolic shaker at 37.5°C for varying time intervals.Analytical methods. At the end of the incubation period the slices were quickly washed five times with 5 ml of cold Krebs-Ringer bicarbonate buffer and homogenized in 1 ml water at on C by grinding with a motor-driven pestle. In experiments in which the ribonucleic acid (RNA) fractions were ...

Metabolism of Testosterone by the Human Prostate

“…Elution of this and development in Kochakian and Stidworthy's benzene cyclohexane system for 40 hours resolved it into 3 peaks we refer to as Proximal [1][2][3] (Fig 2). The A third fact of possible importance is that the 2 main products can theoretically be produced by single enzymatic reductions of testosterone ( Fig 4 ).…”

Further Studies on Rna and Protein Biosynthesis in the Ovariectomized Mouse Uterus

“…Potential support for this hypothesis is provided by studies on RNA pro¬ duction after hormonal therapy (Gorski et al 1965), protein incorporation in the secondary sex organs (Kochakian et . 1962;Williams-Ashman et al 1963;Wilson 1962 and many others), local puromycin application into the vagina of oestrogen treated rats (Talwar 8c Segal 1963) and the direct effect of RNA on the histological picture of the ovariectomized rat uterus .…”

A Double Life: Academic Physician and Androgen Physiologist

“…A leading theory at the time was that steroid hormones influence protein biosynthesis by controlling amino acid transport into cells (17), but I found that testosterone administration increased protein synthesis in the male urogenital tract prior to enhancement of amino acid transport, and the findings indicated that the increase in protein biosynthesis was secondary to an increase in RNA formation (18). In a subsequent study of RNA subtypes, I showed that the enhancement of protein synthesis in rat uterus by estrogen is secondary to an increase in the formation of messenger (then termed template) RNA (19).…”