Regulation of [beta]3-adrenergic receptor mrna by sympathetic
nerves and glucocorticoids in brown adipose tissue of zucker obese
(fa/fa) rats.
Onai, Toru, Gail Kilroy, David A. York, and George A. Bray.
Pennington Biomedical Research Center, 6400 Perkins Road, Baton
Rouge, LA 70808, Department of Physiology, LSU School of Medicine,
New Orleans, LA 70112
APStracts 2:0084R, 1995.
Impaired brown adipose tissue (BAT) thermogenesis in the genetically
obese Zucker fatty fa/fa rat is restored to normal by adrenalectomy.
We investigated the role of the sympathetic nervous system in
modulating the effects of adrenalectomy by studying [beta]3
-adrenergic receptor (AR) and Uncoupling protein (UCP) mRNA levels in
unilaterally sympathectomized interscapular BAT of lean and obese
rats. UCP mRNA levels were increased by adrenalectomy. Sympathetic
denervation prevented this adrenalectomy induced increase in lean
rats, but not in obese rats. [beta]3-AR MRNA was decreased in BAT of
obese rats. Adrenalectomy decreased and denervation increased
[beta]3-AR MRNA in lean rats but the opposite response was observed
to both of these manipulations in obese rats. [beta]3-AR mRNA and UCP
mRNA were negatively correlated in lean rats, but positively
correlated in obese rats. NE increased UCP mRNA levels in denervated
BAT of both lean and obese rats and decreased [beta]3-AR mRNA in lean
rats but not obese rats. These data suggest that the regulation of
the [beta]3-AR gene in response to sympathetic stimuli and
glucocorticoids is abnormal in the obese rat.
Received 14 July 1994; accepted in final form 23 March 1995.
APS Manuscript Number R378-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 April 1995.