Glucocorticoids and insulin: complex interaction on brown adipose
tissue.
Strack, Alison M., Cydney J. Horsley, Raynard J. Sebastian, Susan F. Akana,
and Mary F. Dallman.
Department of Physiology, University of California San Francisco, San
Francisco CA 94143-0444
APStracts 2:0005R, 1995.
Glucocorticoids and insulin effect long-term reciprocal changes in food intake
and body weight. We tested the interactions of corticosterone and insulin on
caloric efficiency, white adipose tissue (WAT) stores and brown adipose
tissue (BAT). Two experiments were performed: adrenalectomized rats were
treated with corticosterone with or without streptozotocin-induced diabetes;
adrenalectomized, corticosterone treated, diabetic rats were treated with
insulin. Four-5 d later, >/=50% of the variance in caloric efficiency, plasma
triglycerides and WAT stores was explained by regression of these variables
on corticosterone (catabolic) and insulin (anabolic). When the ratio of the
hormones was normal, but concentrations high, overall gain of energy stores
decreased and energy was redistributed to fat. Both hormones were anabolic on
BAT lipid storage; the hormones played a complex role in the regulation of
uncoupling protein (UCP) in BAT. Although corticosterone inhibited and
insulin stimulated UCP, these effects were only evident in diabetics and with
normoglycemia, respectively. For BAT variables, </= 50% of the variance was
explained by regression on corticosterone and insulin, suggesting that the
effects of these hormones are mediated through an intermediate such as
sympathetic nervous system input to BAT.
Received 3 August 1994; accepted in final form 6 January 1995.
APS Manuscript Number R428-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative Comp.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 February 1995.