Subclassification of β-adrenergic receptors of rat fat cells

A re-evaluation

Suleiman Bahouth, C. C. Malbon

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Catecholamines regulate lipolysis in rat fat cells via β-adrenergic receptors. Recently, it has been proposed that β-adrenergic receptors of rat fat cells are neither β1 nor β2 in character but rather than an 'isoreceptor', 'hybrid', or 'β3' [Br. J. Pharmacol. 84:131-137 (1985)]. This putative receptor subtype has been envisioned as possessing an alkanolamine side-chain interaction site of β1 nature and an aromatic moiety interaction site of β2 nature. These proposals were evaluated in the present work through a reexamination of the nature of the fat cell β-adrenergic receptor using four radioligands that differ chemically in one or both of these regions of the molecule as well as in their hydrophobicity. Equilibrium binding of agonist and of β1- and β2 subtype-selective high affinity antagonist ligands to fat cell membranes was detailed. The binding sites labeled by these ligands had the characteristics of β1-adrenergic receptors. The rank order of subtype-selective antagonists in competing for radioligand binding to fat cell membranes was the same as that for inhibition of agonist-stimulated cyclic AMP accumulation by these ligands. At equimolar concentrations, the β1-selective antagonist CGP-20712A provided a greater degree of inhibition of catecholamine-stimulated lipolysis than the β2-selective antagonist ICI-118,551. These results document the character of the rat fat cell β-adrenergic receptor as solely β1.

Original languageEnglish (US)
Pages (from-to)318-326
Number of pages9
JournalMolecular Pharmacology
Volume34
Issue number3
StatePublished - 1988
Externally publishedYes

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Adipocytes
Adrenergic Receptors
Lipolysis
Ligands
Catecholamines
Cell Membrane
Hydrophobic and Hydrophilic Interactions
Cyclic AMP
Binding Sites

All Science Journal Classification (ASJC) codes

  • Pharmacology

Cite this

Subclassification of β-adrenergic receptors of rat fat cells : A re-evaluation. / Bahouth, Suleiman; Malbon, C. C.

In: Molecular Pharmacology, Vol. 34, No. 3, 1988, p. 318-326.

Research output: Contribution to journalArticle

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