Differential properties of human chorionic gonadotrophin and human luteinizing hormone binding to plasma membranes of bovine corpora lutea.
Plasma membranes of bovine corpora lutea contain common receptor sites for [125I]human chorionic gonadotrophin (hCG) and [125I]human luteinizing hormone (hLH) to which hLH binds with 4-fold lower affinity than hCG. The presence of additional sites for hLH was indicated by the lack of saturation of [125I]hLH binding as compared to [125]hCG and lower degree of inhibition of binding by 830 pM of unlabelled hCG, when [125I]hLH instead of [125I]hCG was used. Differences in [125I]hCG and [125I]hLH binding were observed by exposing receptors to increasing temperatures and pHs and by pre-treating membranes with dimethyl sulphoxide, Triton X-100, various enzymes and protein reagents. The above differences can only be reconciled by differential responses of common hCGhLH sites and additional sites for hLH.
D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism*; D006063:Chorionic Gonadotropin / Q000378:metabolism*; D003338:Corpus Luteum / Q000378:metabolism*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004798:Enzymes / Q000494:pharmacology; D005260:Female; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D011092:Polyethylene Glycols / Q000494:pharmacology; D011956:Receptors, Cell Surface; D013696:Temperature
D006063:Chorionic Gonadotropin; D004798:Enzymes; D007202:Indicators and Reagents; D008565:Membrane Proteins; D011956:Receptors, Cell Surface; D011092:Polyethylene Glycols; D007986:Luteinizing Hormone; D004121:Dimethyl Sulfoxide