Regional lipolytic responses to isoproterenol in women.
Guo, Zengkui, C. Michael Johnson, Michael D. Jensen.
Endocrine Research Unit, Mayo Clinic, Rochester, MN 55905
APStracts 4:0055E, 1997.
We previously found that epinephrine, a mixed [beta]- and [alpha]
-adrenoreceptor agonist, stimulates systemic and non-splanchnic, upper
body free fatty acid (FFA) release, but not lower body FFA release in
healthy, non-obese women. To evaluate the role of [beta]-adrenergic
-mediated effects on this regional difference in lipolysis, systemic,
leg, and splanchnic FFA kinetics ([3H]palmitate) were measured in 7
healthy, non-obese women before and during an intravenous
isoproterenol infusion. Isoproterenol increased systemic palmitate
flux (87+/-12 vs. 100+/-10 [mu]mol x min-1, P<0.05) but failed
to affect leg (10.8 +/-1.2 vs 11.4 +/- 2.3 [mu]mol x min-1, P=NS) or
splanchnic (10.8 +/- 3.2 vs 10.0 +/- 1.8 [mu]mol x min-1 ,P=NS)
palmitate release. Upper body non-splanchnic palmitate release
increased from 56 +/- 14 to 71 +/- 10 [mu]mol x min-1. Systemic O2
consumption increased (227+/-11 to 241+/-10 ml x min-1, P=0.006)
during isoproterenol infusion, as did leg (318+/-42 vs. 404+/-53 ml x
min-1, P<0.01) and splanchnic (827+/-104 vs. 970+/-108 ml x
min-1, P<0.05) plasma flow. These results suggest that lower
body adipose tissue lipolysis in women is less sensitive or
responsive than non-splanchnic, upper body adipose tissue to [beta]
-adrenergic stimulation and that regional differences in [alpha]2
-adrenergic receptor responses were not responsible for the similar
regional differences we observed previously with epinephrine.
Received 28 October 1996; accepted in final form 18 February
1997.
APS Manuscript Number E534-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 12 March 1997