Role of phospholipids in the accessibility of LH/hCG receptors in porcine corpora lutea.
The role of phospholipids in the interaction of LH/hCG with membrane-bound and water-soluble receptors was studied. Digestion of porcine corpora lutea (CL) membranes with phospholipase-A2 (PL-A2) diminished, in a dose dependent manner, both phospholipid concentration and binding of 125I-hCG to CL membranes. Treatment of the water-soluble LH/hCG receptor occurring in follicular fluid with PL-A2 produced no inhibitory effect on gonadotropin binding in spite of digestion of phospholipids. The decrease of the accessibility of LH/hCG receptors in CL membranes by PL-A2 was associated with a rise of the rigidity of membrane lipids. Dynamic properties of membranes were monitored by electron spin resonance of 5- and 16-doxyl stearic acid probes. These findings suggest that phospholipids play an important role in the accessibility of membrane-bound LH/hCG receptors, but are not involved in a direct interaction of gonadotropin with the binding sites.
Kolena
J
J
Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava.
Danisová
A
A
Matejcíková
K
K
D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D006063:Chorionic Gonadotropin / Q000378:metabolism; D003338:Corpus Luteum / Q000378:metabolism*; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D005260:Female; D008560:Membrane Fluidity; D010741:Phospholipases A / Q000494:pharmacology; D054467:Phospholipases A2; D010743:Phospholipids / Q000502:physiology*; D011974:Receptors, LH / Q000378:metabolism*; D012997:Solvents; D013113:Spin Labels; D013552:Swine
D006063:Chorionic Gonadotropin; D003497:Cyclic N-Oxides; D010743:Phospholipids; D011974:Receptors, LH; D012997:Solvents; D013113:Spin Labels; C005072:5-doxylstearic acid; C032363:16-nitroxystearic acid; D010741:Phospholipases A; D054467:Phospholipases A2