AJP - Cell Physiology, Vol 254, Issue 1 C175-C182, Copyright © 1988 by American Physiological Society

ARTICLES

Beta-adrenergic stimulation of brown adipocyte proliferation

A. Geloen, A. J. Collet, G. Guay and L. J. Bukowiecki
Department of Physiology, Medical School, Laval University, Quebec City, Canada.

The mechanisms of brown adipose tissue (BAT) growth were studied by quantitative photonic radioautography using tritiated thymidine to follow mitotic activity. To identify the nature of the adrenergic pathways mediating brown adipocyte proliferation and differentiation, the effects of cold exposure (4 days at 4 degrees C) on BAT growth were compared with those induced by treating rats at 25 degrees C with norepinephrine (a mixed agonist), isoproterenol (a beta-agonist), and phenylephrine (an alpha-agonist). The drugs were continuously administrated via osmotic minipumps (0.375 mumol/h during 4 days) implanted subcutaneously. Cold exposure markedly enhanced the mitotic activity in brown adipocyte precursor cells (interstitial cells and preadipocytes) and endothelial cells forming the numerous capillaries. Norepinephrine mimicked the effects of cold exposure, not only on the mitotic activity, but also on the distribution of the labeling among the various cellular types. Isoproterenol entirely reproduced the effects of norepinephrine both on the labeling index and on the cellular type labeling frequency. In contrast, phenylephrine did not stimulate cell division. These results demonstrate that norepinephrine triggers a coordinated proliferation of brown adipocytes and endothelial cells in warm-exposed rats that is similar to that observed after cold exposure. They also suggest that cold exposure stimulates BAT growth by increasing the release of norepinephrine from sympathetic nerves and that the neurohormone activates mitoses in BAT precursor cells via beta-adrenergic pathways.

This article has been cited by other articles:

				S. M. Wilson, S. C. Lee, S. Shook, and P. A. Pappone ATP and beta -adrenergic stimulation enhance voltage-gated K current inactivation in brown adipocytes Am J Physiol Cell Physiol, December 1, 2000; 279(6): C1847 - C1858. [Abstract] [Full Text] [PDF]

				J. M. Fredriksson, J. M. Lindquist, G. E. Bronnikov, and J. Nedergaard Norepinephrine Induces Vascular Endothelial Growth Factor Gene Expression in Brown Adipocytes through a beta -Adrenoreceptor/cAMP/Protein Kinase A Pathway Involving Src but Independently of Erk1/2 J. Biol. Chem., April 28, 2000; 275(18): 13802 - 13811. [Abstract] [Full Text] [PDF]

				A. Chaudhry and J. G. Granneman Differential regulation of functional responses by beta -adrenergic receptor subtypes in brown adipocytes Am J Physiol Regulatory Integrative Comp Physiol, July 1, 1999; 277(1): R147 - R153. [Abstract] [Full Text] [PDF]

				X. Liu, F. Perusse, and L. J. Bukowiecki Mechanisms of the antidiabetic effects of the beta 3-adrenergic agonist CL-316243 in obese Zucker-ZDF rats Am J Physiol Regulatory Integrative Comp Physiol, May 1, 1998; 274(5): R1212 - R1219. [Abstract] [Full Text] [PDF]

				M. Florez-Duquet, B. A. Horwitz, and R. B. McDonald Cellular proliferation and UCP content in brown adipose tissue of cold-exposed aging Fischer 344 rats Am J Physiol Regulatory Integrative Comp Physiol, January 1, 1998; 274(1): R196 - R203. [Abstract] [Full Text] [PDF]

				P. Tvrdik, A. Asadi, L. P. Kozak, J. Nedergaard, B. Cannon, and A. Jacobsson Cig30, a Mouse Member of a Novel Membrane Protein Gene Family, Is Involved in the Recruitment of Brown Adipose Tissue J. Biol. Chem., December 12, 1997; 272(50): 31738 - 31746. [Abstract] [Full Text] [PDF]

				C. Atgie, F. D'Allaire, and L. J. Bukowiecki Role of beta 1- and beta 3-adrenoceptors in the regulation of lipolysis and thermogenesis in rat brown adipocytes Am J Physiol Cell Physiol, October 1, 1997; 273(4): C1136 - C1142. [Abstract] [Full Text] [PDF]

				B. Garcia and M.-J. Obregon Growth factor regulation of uncoupling protein-1 mRNA expression in brown adipocytes Am J Physiol Cell Physiol, January 1, 2002; 282(1): C105 - C112. [Abstract] [Full Text] [PDF]