AJP - Endocrinology and Metabolism, Vol 266, Issue 2 E155-E160, Copyright © 1994 by American Physiological Society
Changes in lipolytic sensitivity following repeated epinephrine infusion in humans
R. R. Townsend, S. Klein and R. R. Wolfe
Department of Medicine, University of Texas Medical Branch, Galveston.
The lipolytic response to epinephrine is increased in lean but not obese
subjects during conditions of increased circulating catecholamines such as
starvation and critical illness. We evaluated the effect of repeated
epinephrine treatment (0.03 micrograms.kg-1.min-1 for 30 min thrice daily)
on basal lipolysis and the lipolytic response to epinephrine in lean and
obese subjects. Lipolytic rates were determined using [2H5]glycerol during
basal conditions and 60 min of epinephrine infusion before and after 6 days
of repeated epinephrine treatment. Basal lipolysis and the lipolytic
response to epinephrine were higher in obese (2.47 +/- 0.51
mumol.kg-1.min-1 and 106 +/- 21 mumol/kg, respectively) than lean (1.45 +/-
0.15 mumol.kg-1.min-1 and 70 +/- 12 mumol/kg, respectively; P = 0.08 obese
vs. lean) subjects. Repeated epinephrine treatment decreased basal glycerol
rate of appearance and the lipolytic response to epinephrine in lean and
obese subjects. Plasma insulin concentration increased after repeated
epinephrine treatment in both obese (14.3 +/- 0.6 to 18.2 +/- 1.6
microU/ml; P < 0.05) and lean (8.4 +/- 1.3 to 11.1 +/- 1.5 microU/ml; P
< 0.01) subjects. Repeated epinephrine treatment suppresses basal and
epinephrine-stimulated lipolysis. Increased plasma insulin concentration
may be the mechanism.
