Insulin-stimulated glucose uptake is enhanced in sedentary and endurance-trained low insulin responders
Pigon, J.; Efendić, S.; Ostenson, C.G.; Lam, L.; Vranić, M.; Giacca, A.
American Journal of Physiology 268(6 Pt 1): E1046-E1050
1995
ISSN/ISBN: 0002-9513 PMID: 7611377 Document Number: 453287
The mechanisms by which healthy sedentary subjects with low insulin response (LORE; 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 LORE, 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 hyperinsulinemic euglycemic clamps using the "hot-GINF" method with high-pressure liquid chromatography purified (6-3H)glucose. All groups had a similar basal glucose appearance rate (R-a). During clamps, plasma insulin levels were doubled to 169 +- 9 pmol/l, whereas R-a decreased similarly in all groups. Glucose utilization rate increased more in LORE and ET than in HIR (to 20.9 +- 1.5 mu-mol cntdot kg-1 cntdot min-1 in LORE, P lt 0.001 vs. HIR; 27.4 +- 3.6 in ET, P lt 0.01 vs. HIR and LORE; and 14.3 +- 0.6 in HIR). In conclusion, the present study demonstrates increased insulin sensitivity in LORE and ET with respect to glucose uptake but not glucose production.