AJP - Regulatory, Integrative and Comparative Physiology, Vol 266, Issue 3 896-R904, Copyright © 1994 by American Physiological Society

ARTICLES

Predominance of beta 3-adrenergic component in catecholamine activation of lipolysis in garden dormouse adipocytes

C. Carpene, L. Ambid and M. Lafontan
Institut National de la Sante et de la Recherche Medicale, Universite Paul Sabatier, France.

The beta 3-adrenoceptor (AR) agonists are potent activators of lipolysis in white adipose tissue. beta-AR agonists were tested here on the lipolytic activity of a hibernator, the garden dormouse (Eliomys quercinus L.). All the agonists exhibited full intrinsic activity; the most potent was the beta 3-AR agonist BRL-37344 [half-maximal effective concentration (EC50) = 0.8 nM]. The beta-antagonist idocyanopindolol (ICYP) also stimulated lipolysis of white adipocytes with the same potency and intrinsic activity as BRL-37344. The blockade of lipolytic effects of epinephrine or norepinephrine was similar to that of BRL-37344: the beta 1- and the beta 2-antagonists were quite ineffective. Total blockade occurred only with 100 microM bupranolol whatever the beta-agonist tested. This argues for the presence of a beta 3-component in the adrenergic-induced lipolysis. (-)-[125I]ICYP and (-)-[3H]CGP-12177 both labeled two populations of binding sites. On adipocyte membranes, binding of 0.6 nM (-)-[3H]CGP-12177 was inhibited with the following order of potency: isoproterenol > BRL-37344 > epinephrine. This order was modified at 20 nM, arguing for the beta-atypical nature of the low-affinity sites. Thus garden dormouse adipocytes possess beta 3-ARs, which are involved to an important degree in the adrenergic activation of lipolysis.

This article has been cited by other articles:

				N. Morin, J.-M. Lizcano, E. Fontana, L. Marti, F. Smih, P. Rouet, D. Prévot, A. Zorzano, M. Unzeta, and C. Carpéné Semicarbazide-Sensitive Amine Oxidase Substrates Stimulate Glucose Transport and Inhibit Lipolysis in Human Adipocytes J. Pharmacol. Exp. Ther., April 12, 2001; 297(2): 563 - 572. [Abstract] [Full Text]

				E. Farias-Silva, D. M. Grassi-Kassisse, V. Wolf-Nunes, and R. C. Spadari-Bratfisch Stress-induced alteration in the lipolytic response to {beta}-adrenoceptor agonists in rat white adipocytes J. Lipid Res., September 1, 1999; 40(9): 1719 - 1727. [Abstract] [Full Text]