Characteristics of binding of human seminal alpha-inhibin-92 to human pituitary membranes.
We investigated the binding of 125I-labeled alpha-inhibin-92 (a 92-residue peptide) to human pituitary membrane preparations. Unlabeled alpha-inhibin-92 competed effectively with the labeled peptide for binding to the membranes. Binding was also inhibited by both alpha-inhibin-52 and alpha-inhibin-31, but less effectively. Scatchard analysis of the alpha-inhibin-92 binding data indicated the presence of high-affinity binding sites (1.35 nM/mg of membrane protein) with an apparent Kd of 0.37 nM. When 125I-labeled alpha-inhibin-92 was covalently crosslinked to the pituitary membrane preparation with disuccinimidyl suberate and the solubilized labeled receptor complex was analyzed by NaDodSO4/PAGE under either reducing or nonreducing conditions, a single radioactive band at an apparent molecular weight of 90,000 +/- 5000 was observed. These data suggest that human pituitary has specific binding sites for alpha-inhibins.
D029404:Activin Receptors; D001665:Binding Sites; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D007265:Inhibins / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D010902:Pituitary Gland / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018000:Receptors, Peptide; D012661:Semen / Q000378:metabolism*
D011956:Receptors, Cell Surface; D018000:Receptors, Peptide; D007265:Inhibins; C051562:alpha-inhibin-92; D029404:Activin Receptors