Insulin-stimulated glucose uptake is enhanced in sedentary and endurance
trained low insulin responders.
Pigon, Jan, Suad Efendic', Claes-G[diaeresis]oran [diaeresis]ostenson, Loretta
Lam, Mladen Vranic', Adria Giacca.
Department of Molecular Medicine, Diabetes and Endocrinology Unit,
Karolinska Institute, S-171 76 , Stockholm, Sweden, and, Department of
Physiology and Medicine, University of Toronto, Toronto, Ontario, M5S1A8,
Canada
APStracts 2:0008E, 1995.
The mechanisms, by which healthy, sedentary subjects with low insulin response
(LIR; 5 min. insulin response to glucose load within lowest quartile of
healthy population) maintain a normal glucose tolerance, are not clear. We
studied glucose uptake and hepatic glucose production in LIR, in healthy
subjects with high insulin response (HIR; two highest quartiles of insulin
response) matched for weight and physical fitness and in endurance trained
subjects (ET). For this purpose we performed hyperinsulinaemic euglycaemic
clamps using "hot-GINF" method with HPLC purified 6-3H-glucose. All groups
had a similar basal glucose appearance rate, Ra. During clamps, plasma
insulin levels were doubled to 169+/-9 pmol/l, while Ra decreased similarly in
all groups. Glucose utilization rate increased more in LIR and ET than in HIR
(to 20.9+/-1.5 [mu]mol/kg x min in LIR; p<0.001 vs. HIR, 27.4+/-3.6 in ET;
p<0.01 vs. HIR and LIR, and 14.3+/-0.6 in HIR). In conclusion, the present
study demonstrates increased insulin sensitivity in LIR and ET with respect to
glucose uptake but not glucose production.
Received 12 October 1994; accepted in final form 9 January 1995.
APS Manuscript Number E419-4.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 February 1995.