title: The effect of calcium ions on testosterone production in Leydig cells from rat testis.
abstract: Leydig-cell suspensions, prepared from rat testes, were incubated with different amounts of Ca2+ with and without added luteinizing hormone. The basal testosterone production in the absence of luteinizing hormone was unaffected by the Ca2+ concentration in the incubation medium. The luteinizing hormone-stimulated testosterone production, however, was progressively decreased in the absence of Ca2+ to one-third of that with 2.50 mM-Ca2+. This decrease in luteinizing hormone-stimulated testosterone production was independent of the different concentrations of luteinizing hormone (0-10mug/ml) used and could be restored by the addition of Ca2+ to the incubation medium. The restoration of the stimulation was achieved within 30 min after the addition of Ca2+ to the medium. Activation of cyclic AMP-dependent protein kinase by luteinizing hormone was not decreased by omission of Ca2+ from the incubation medium, suggesting that Ca2+ may be involved in steroidogenesis at a stage beyond the luteinizing hormone receptor-adenylate cyclase-protein kinase system.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D004789:Enzyme Activation; D066298:In Vitro Techniques; D007985:Leydig Cells / Q000201:enzymology / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000494:pharmacology; D008297:Male; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D013268:Stimulation, Chemical; D013739:Testosterone / Q000096:biosynthesis*
chemical_list: D013739:Testosterone; D007986:Luteinizing Hormone; D011494:Protein Kinases; D002118:Calcium