AJP - Endocrinology and Metabolism, Vol 267, Issue 6 E941-E946, Copyright © 1994 by American Physiological Society
Effect of antilipolysis on heart and skeletal muscle glucose uptake in overnight fasted humans
P. Nuutila, M. J. Knuuti, M. Raitakari, U. Ruotsalainen, M. Teras, L. M. Voipio-Pulkki, M. Haaparanta, O. Solin, U. Wegelius and H. Yki-Jarvinen
Department of Medicine, University of Turku, Finland.
We quantitated how lowering of free fatty acid (FFA) by an antilipolytic
agent (acipimox) in the fasting state changes glucose uptake in heart and
skeletal muscles. Glucose uptake in these tissues was measured two times in
seven normal subjects, once after acipimox and once after placebo, using
positron emission tomography-derived [18F]fluoro-2-deoxy-D-glucose
kinetics. Plasma glucose and insulin remained at their fasting
concentrations in both studies. Fasting FFA concentrations were 60% lower
after acipimox (238 +/- 39) than placebo (645 +/- 78 mumol/l, P <
0.001). Glucose uptake increased 6 +/- 2-fold in the heart by acipimox (344
+/- 49 vs. 108 +/- 40 mumol.kg muscle-1.min-1, P < 0.002) and 1.5-fold
in arm muscles (27.7 +/- 2.6 vs. 18.6 +/- 1.2 mumol.kg muscle-1.min-1, P
< 0.02). Heart (r = -0.93, P < 0.001) and arm (r = -0.82, P <
0.001) glucose uptakes were inversely related to serum FFA. We conclude
that serum FFA are inversely related to glucose uptake in heart and arm
skeletal muscles after an overnight fast. These data indicate that
compensatory glycogenolysis, although it may occur, does not prevent
operation of the glucose-FFA cycle under fasting conditions.
