AJP - Endocrinology and Metabolism, Vol 273, Issue 1 E108-E112, Copyright © 1997 by American Physiological Society
Regional lipolytic responses to isoproterenol in women
Z. Guo, C. M. Johnson and M. D. Jensen
Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55905, USA.
We previously found that epinephrine, a mixed beta- and
alpha-adrenoreceptor agonist, stimulates systemic and nonsplanchnic upper
body free fatty acid (FFA) release but not lower body FFA release in
healthy nonobese women. To evaluate the role of beta-adrenergic-mediated
effects on this regional difference in lipolysis, we measured systemic,
leg, and splanchnic FFA kinetics ([3H]palmitate) in seven healthy nonobese
women before and during an intravenous isoproterenol infusion.
Isoproterenol increased systemic palmitate flux (87 +/- 12 vs. 100 +/- 10
mumol/min, P < 0.05) but failed to affect leg [10.8 +/- 1.2 vs. 11.4 +/-
2.3 mumol/min, P = not significant (NS)] or splanchnic (10.8 +/- 3.2 vs.
10.0 +/- 1.8 mumol/min, P = NS) palmitate release. Upper body nonsplanchnic
palmitate release increased from 56 +/- 14 to 71 +/- 10 mumol/min. Systemic
O2 consumption increased (227 +/- 11 to 241 +/- 10 ml/min, P = 0.006)
during isoproterenol infusion, as did leg (318 +/- 42 vs. 404 +/- 53
ml/min, P < 0.01) and splanchnic (827 +/- 104 vs. 970 +/- 108 ml/min, P
< 0.05) plasma flow. These results suggest that lower body adipose
tissue lipolysis in women is less sensitive or responsive than
nonsplanchnic 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.
