title: The hormone-binding unit of luteinizing hormone receptor.
abstract: Rat ovarian luteinizing hormone/human choriogonadotropin binding sites were labelled with 125I-choriogonadotropin in vivo, and the resulting 125I-choriogonadotropin-receptor complexes were solubilized by Triton X-100 and purified by use of antibodies to choriogonadotropin immobilized to agarose. The purified 125I-choriogonadotropin-receptor complex was treated with glutaraldehyde to crosslink radiolabelled hormone to the receptor. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of the crosslinked product revealed a labelled Mr 130 000 major band in addition to the hormone and its alpha-subunit, indicating that a single receptor component was linked to the hormone. Unoccupied binding sites for luteinizing hormone were also solubilized by Triton X-100 from pseudopregnant rat ovaries, and attached to choriogonadotropin-agarose. The agarose gel was washed, and eluted with 0.1 M-sodium acetate, pH 4. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of the pH 4 eluate revealed an Mr 90 000 major band which was abolished when ovaries presaturated with choriogonadotropin were used as starting material. These observations suggest that the hormone-binding component of the luteinizing hormone receptor is a polypeptide of Mr 90 000. This polypeptide was isolated and labelled with Na 125I. The labelled polypeptide showed a single band on sucrose density gradient centrifugation and on gel filtration on agarose.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002846:Chromatography, Affinity; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005976:Glutaral / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000378:metabolism*; D046911:Macromolecular Substances; D010455:Peptides / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D011974:Receptors, LH
chemical_list: D003432:Cross-Linking Reagents; D046911:Macromolecular Substances; D010455:Peptides; D011956:Receptors, Cell Surface; D011974:Receptors, LH; D007986:Luteinizing Hormone; D005976:Glutaral