Androgens decrease LHRH binding sites in rat anterior pituitary cells in culture.
[125I]-[D-Ser(TBU)6]LHRH-EA binds to a single class of high affinity sites in rat anterior pituitary cells in culture at an apparent dissociation constant of 0.25 nM at 0-4C. The order of potency of a representative group of LHRH agonists and antagonists to displace the labeled ligand is similar to their LH-releasing activity. Treatment of pituitary cells for 48 h with 100 nM 5 alpha-dihydrotestosterone leads to a 40% decrease of the number of LHRH receptors with no change of binding affinity. This loss of LHRH receptors is accompanied by a similar decrease of the LH responsiveness to LHRH, thus providing the first evidence for a direct effect of sex steroids on pituitary LHRH receptors as a possible mechanism of feedback action.
D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D001667:Binding, Competitive; D002478:Cells, Cultured; D013196:Dihydrotestosterone / Q000494:pharmacology; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007700:Kinetics; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011966:Receptors, LHRH
D000728:Androgens; D011956:Receptors, Cell Surface; D011966:Receptors, LHRH; D013196:Dihydrotestosterone; D007987:Gonadotropin-Releasing Hormone