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LHRH‐PITUITARY PLASMA MEMBRANE BINDING: THE PRESENCE OF SPECIFIC BINDING SITES IN OTHER TISSUES
Author(s) -
MARSHALL J. C.,
SHAKESPEAR R. A.,
ODELL W. D.
Publication year - 1976
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1976.tb03870.x
Subject(s) - membrane , receptor , anterior pituitary , binding site , endocrinology , medicine , pituitary gland , chemistry , kinetics , receptor–ligand kinetics , cell surface receptor , biology , biochemistry , hormone , physics , quantum mechanics
Summary Two specific binding sites for LHRH are present on plasma membranes prepared from rat and bovine anterior pituitary glands. One site is of high affinity (K = 2 ±10 8 1/mol) and the second is of lower affinity (8.5 ±10 5 1/mol) and much greater capacity. Studies on membrane fractions prepared from other tissues showed the presence of a single specific site for LHRH. The kinetics and specificity of this site were similar to those of the lower affinity pituitary receptor. These results indicate that only pituitary membranes possess the higher affinity binding site and suggest that the low affinity site is not of physiological importance in the regulation of gonadotrophin secretion. After dissociation from membranes of non‐pituitary tissues 125 I‐LHRH rebound to pituitary membrane preparations. Thus receptor binding per se does not result in degradation of LHRH and the function of these peripheral receptors remains obscure.