Effect of phospholipase C induced hydrolysis of phospholipids on membrane-bound and water-soluble LH/hCG receptors in porcine corpora lutea.
The role of phospholipids in the function of LH/hCG receptors was studied in two receptor preparations: the membrane fraction of porcine corpora lutea (CL) and the water-soluble receptor in follicular fluid (LFF) which was characterized. Digestion of CL membranes with phospholipase C (PL-C) abolished, in a dose responsive manner, specific binding of [125I]hCG and decreased phospholipid concentrations in the membranes. This loss of LH/hCG receptors was prevented by o-phenanthroline, an inhibitor of PL-C. A similar effect on membrane-bound receptors was observed when lipids were extracted with ethanol-diethylether. On the other hand, treatment of water-soluble receptors with PL-C or delipidation of LFF with Amberlit IRA 400 had no effect on [125I]hCG specific binding. These data suggest that phospholipids play an important role in the accessibility of membrane-bound receptors but are not involved in direct interaction of gonadotropin with binding sites.
Kolena
J
J
Institute of Experimental Endocrinology, Slovak Academy of Sciences.
D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D006063:Chorionic Gonadotropin / Q000378:metabolism / Q000502:physiology; D003338:Corpus Luteum / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D005260:Female; D006868:Hydrolysis / Q000187:drug effects; D007457:Iodine Radioisotopes; D010743:Phospholipids / Q000032:analysis / Q000378:metabolism* / Q000502:physiology; D011485:Protein Binding; D011967:Receptors, Gonadotropin / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D011974:Receptors, LH / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D013552:Swine; D010738:Type C Phospholipases / Q000494:pharmacology*
D006063:Chorionic Gonadotropin; D007457:Iodine Radioisotopes; D010743:Phospholipids; D011967:Receptors, Gonadotropin; D011974:Receptors, LH; D010738:Type C Phospholipases