HORMONAL-REGULATION OF HUMAN TESTICULAR INHIBIN-ALPHA AND BETA(B)-SUBUNIT MESSENGER-RNAS

Changes in messenger ribonucleic acids (mRNAs) of human testicular inh ibin alpha and beta(B) subunits induced by human menopausal gonadotrop in (hMG) and human chorionic gonadotropin (hCG) were assessed in vivo and in vitro. After a single administration of hMG, inhibin alpha mRNA in the human testis significantly increased, whereas inhibin beta(B) mRNA remained unchanged. Administration of hCG induced a slight increa se in inhibin alpha mRNA without affecting inhibin beta(B) mRNA. In ex periments in vitro using the testicular organ culture technique, an ex posure to hMG for 24 hours induced a dose-related significant increase in inhibin alpha mRNA. Inhibin beta(B) mRNA was not affected by eithe r hCG or hMG exposure. These results indicate that luteinizing hormone (hCG) as well as follicle stimulating hormone (hMG) may play a role i n the regulation of human testicular inhibin alpha mRNA, although the mechanism of the LH action is not clear.