title: Demonstration of luteinizing hormone/human chorionic gonadotrophin receptor-binding inhibitor in aqueous extracts of frozen human corpus luteum.
abstract: Aqueous extracts of frozen human corpora lutea were tested for the presence of an inhibitor of luteinizing hormone-receptor site binding (LHRBI) and for the subsequent effect on the stimulatory response of luteinizing hormone (LH) on progesterone synthesis by sheep ovarian cells. In the presence of human corpus luteum extract of normal menstrual cycle (30,000-g supernatant), the binding of 125I human chorionic gonadotrophin (hCG) to granulosa and luteal cells of sheep ovaries was markedly reduced, but the ability of rat testicular LH receptors to bind labelled hCG was less affected. However, extracts of corpora lutea of the first trimester of pregnancy appeared to be less inhibitory on the binding of LH/hCG to ovarian cells and had no effect on the binding of rat testicular cells compared to those of normal menstrual cycle. Addition of both extracts separately inhibited the LH-stimulated in vitro progesterone synthesis by granulosa cell cultures and by incubated sheep corpus luteum slices. These findings provide evidence for the presence of LHRBI in human corpus luteum.
mesh_terms: D000818:Animals; D006063:Chorionic Gonadotropin / Q000378:metabolism*; D003338:Corpus Luteum / Q000032:analysis*; D005260:Female; D006107:Granulosa Cells / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D036341:Intercellular Signaling Peptides and Proteins; D008184:Luteal Cells / Q000378:metabolism; D008297:Male; D008598:Menstruation; D010455:Peptides; D011247:Pregnancy; D051381:Rats; D011956:Receptors, Cell Surface / Q000032:analysis / Q000037:antagonists & inhibitors* / Q000187:drug effects*; D011966:Receptors, LHRH; D012756:Sheep; D013737:Testis / Q000378:metabolism; D014020:Tissue Extracts / Q000032:analysis
chemical_list: D006063:Chorionic Gonadotropin; D036341:Intercellular Signaling Peptides and Proteins; C011898:LH receptor binding inhibitor; D010455:Peptides; D011956:Receptors, Cell Surface; D011966:Receptors, LHRH; D014020:Tissue Extracts