Expression and regulation of two steps of steroidogenesis in human Leydig cells × murine cell line Clone 1D hybrids

Abstract

In an attempt to analyse the possible interactions between differentiated and undifferentiated genomes and also, in order to study the role of polypeptidic hormones in cell differentiation, we prepared hybrids between human Leydig cells and the murine cell line Clone 1D. Fifteen independent hybrid clones were analysed for steroid metabolism: 10 positive hybrids converted significantly dehydroepiandrosterone (DHA) to testosterone following stimulation with dibutyryl cAMP but only 8 of them were shown to produce significant amounts of testosterone under basal conditions. The activity of Clone 1D was negligible in both cases. Therefore, the expression in basal conditions and the control by dibutyryl cAMP of the two enzymes involved (3β-hydroxysteroid dehydrogenase isomerase and 17-ketoreductase) were not linked in the hybrids, suggesting that they are under the control of independent genes.