PMID: 6535446Jan 1, 1984Paper

Kinetics of the steroidogenic response of the testis to stimulation by hCG. V. Blockade of 17-20 lyase induced by hCG is an age-dependent phenomenon inducible by pre-treatment with hCG

Annales d'endocrinologie
M G Forest, R Roulier

Abstract

The series of events, evidenced in animals after a single injection of human chorionic gonadotrophin (hCG): down-regulation of LH/hCG membrane receptors, uncoupling between receptors and the adenylate cyclase, also includes a blockade of testicular steroidogenesis beyond cyclic-AMP formation, including an inhibition of the 17 alpha-hydroxylase-17, 20-desmolase enzymatic complex. This complex phenomenon, named hCG-induced testicular desensitization also occurs in adult men. Since it is not known if and when these effects are initiated during sexual maturation, we have investigated the kinetics of responses of plasma testosterone (T), its two immediate precursors, delta 4-androstenedione (delta 4) and 17 alpha-hydroxprogesterone (OHP), and 17 beta-estradiol (E2) for a week after a single injection of hCG given at the same dosage (100 IU/kg body weight) in subjects not yet exposed to adult levels of endogenous LH, ie prepubertal boys and untreated hypogonadotrophic hypogonadic (HH) adult men. The HH subjects have been restudied after 3 months of a weekly injection of the hCG at the same dosage. In immature individuals, the effect of hCG on testicular steroidogenisis was strikingly different from that observed previously in adults:...Continue Reading

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