Expression of the human inhibin α-subunit gene in preovulatory granulosa-theca cells

Inhibin, a gonadal peptide that suppresses pituitary follicle-stimulating hormone, with lesser or no effect on luteinizing hormone, has recently been purified and the complementary deoxyribonucleic acid sequences cloned. Inhibin contains two subunits, labeled α-subunit and β-subunit. Here we report for the first time the detection of human inhibin α-subunit gene expression in preovulatory granulosa-theca cells by Northern analysis. The transcript is the same size as previously reported for human placenta and corpus luteum, suggesting that the same gene is being expressed in all three tissues. These findings are consistent with previously reported Southern analysis of deoxyribonucleic acid, which showed only one copy of the α-inhibin gene in the human genome. Thus current data strongly suggest that there is only one copy of the inhibin α-subunit gene in the human genome, and this same gene is expressed in granulosa-theca cells, corpus luteum, and placenta.