alpha-Adrenergic receptors in human adipocyte membranes: direct determination by [3H]yohimbine binding

The Journal of Clinical Endocrinology and Metabolism
M D TharpR J Lefkowitz

Abstract

The presence of alpha 2-adrenergic receptors in membranes derived from human sc adipose tissue was directly demonstrated with a new alpha 2-selective ligand, [3H]yohimbine. Binding of this radiolabeled antagonist to adipocyte membranes was of high affinity (Kd = 3.9 +/- 2.4 nM) and saturable. Computer modelling of [3H]yohimbine saturation curves demonstrated that it binds to a homogeneous class of sites with a density of 145.0 +/- 33.8 fmol/mg protein. Adrenergic agonists competed with [3H]yohimbine in the order expected of alpha-receptors, and their binding was strongly influenced by guanine nucleotides. Competition of alpha-antagonists with this radioligand demonstrated yohimbine to be more potent than prazosin, indicative of alpha 2-receptors. Antagonist binding was unaffected by guanine nucleotides. Paired saturation curves in these adipocyte membranes with the alpha 2-selective [3H]yohimbine and the nonsubtype selective alpha-antagonist [3H]dihydroergocryptine demonstrated similar receptor concentrations. [3H]Dihydroergocryptine has been previously shown to label both alpha 3- and alpha 2-receptors with equal affinity. Therefore, these data indicate that the vast majority of alpha-receptors in human sc fat are of the alpha...Continue Reading

Citations

Dec 1, 1982·Naunyn-Schmiedeberg's Archives of Pharmacology·B RouotJ Schwartz
Dec 9, 1983·European Journal of Pharmacology·N G MorganJ H Exton
Jan 29, 1986·European Journal of Pharmacology·K E DickinsonP S Sever
May 1, 1985·Pharmacology, Biochemistry, and Behavior·D B Bylund
Jan 1, 1983·Progress in Neuro-psychopharmacology & Biological Psychiatry·C B SmithA P Zis
Jan 1, 1984·Comparative Biochemistry and Physiology. C, Comparative Pharmacology and Toxicology·H J Mersmann
Jul 1, 1982·The New England Journal of Medicine·H J Motulsky, P A Insel
Jan 1, 1982·Clinical and Experimental Hypertension. Part A, Theory and Practice·A V ChobanianA Pitruzella
Mar 1, 1983·Clinics in Endocrinology and Metabolism·B B Hoffman
Nov 1, 1984·Acta Pharmacologica Et Toxicologica·S SteenK E Andersson
Jan 1, 1982·Acta Medica Scandinavica. Supplementum·J E Wikberg
May 1, 1983·Scandinavian Journal of Clinical and Laboratory Investigation·P EngfeldtJ Ostman
May 31, 1984·Biochemical and Biophysical Research Communications·S Titinchi, B Clark

❮ Previous
Next ❯

Related Concepts

Related Feeds

Adrenergic Receptors: Trafficking

Adrenergic receptor trafficking is an active physiological process where adrenergic receptors are relocated from one region of the cell to another or from one type of cell to another. Discover the latest research on adrenergic receptor trafficking here.