In vivo incorporation of acetate-1-¹⁴C into testosterone, androstenediol, dehydroepiandrosterone, and the progestogens by the ram testis following human chorionic gonadotropin administration

Abstract

Cannulation of the testicular artery and spermatic vein of the ram and infusion of acetate-1-¹⁴ C at a constant rate of 0.2 ml/min for three hours resulted in a system for study of testicular steroid pathways. This technique emphasized minimum surgical and post-operative stress. Spermatic vein blood was collected 1, 2 and 3 hours following the start of infusion, and the testis was excised the third hour at the end of infusion. Pretreatment with 15,000 IU of hCG for 48 hours and infusion of 5,000 IU hCG was compared to saline treatment in four rams. Steroids were measured for ¹⁴C content following fractionation and purification by conventional methods, including chromatography on thin layer plates, paper, formation of derivatives and crystallization. The uptake of ¹⁴C into the following steroids in decreasing order was testosterone, dehydroepiandrosterone, androstenediol, 17, 20 alpha-dihydroxyprogesterone and 17-hydroxyprogesterone as demonstrated in hCG treated rams. Androstenediol-¹⁴C and 17, 20 alpha-dihydroxyprogesterone-¹⁴C were uncorrected for procedural loss. Those rams not stimulated showed no uptake in the steroids studied. There was no radio-activity isolated in pregnenediol, 17, 20 beta-dihydroxyprogesterone, 20 alpha- and 20 beta-hydroxyprogesterone from either the hCG stimulated or nonstimulated ram. 20 alphahydroxysteroid dehydrogenase was demonstrated to be actively present in the ram testis by formation of 17, 20 alpha-dihydroxyprogesterone-¹⁴C; however, its significance is not yet explained in this species..