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Stimulatory effect of insulin on glucose uptake by muscle involves the central nervous system in insulin-sensitive mice

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Author: Coomans, C.P. · Biermasz, N.R. · Geerling, J.J. · Guigas, B. · Rensen, P.C.N. · Havekes, L.M. · Romijn, J.A.
Type:article
Date:2011
Source:Diabetes, 12, 60, 3132-3140
Identifier: 445720
doi: doi:10.2337/db10-1100
Keywords: Biology · adenosine triphosphate sensitive potassium channel · glucose · insulin · tolbutamide · adipose tissue · animal experiment · animal tissue · article · central nervous system · controlled study · diet · gluconeogenesis · glucose transport · heart · hyperinsulinemia · insulin resistance · insulin sensitivity · lateral brain ventricle · male · mouse · muscle · nonhuman · obesity · priority journal · signal transduction · stimulation · Healthy Living · Life · MHR - Metabolic Health Research · EELS - Earth, Environmental and Life Sciences

Abstract

OBJECTIVE - Insulin inhibits endogenous glucose production (EGP) and stimulates glucose uptake in peripheral tissues. Hypothalamic insulin signaling is required for the inhibitory effects of insulin on EGP. We examined the contribution of central insulin signaling on circulating insulin-stimulated tissue-specific glucose uptake. RESEARCH DESIGN AND METHODS - Tolbutamide, an inhibitor of ATP-sensitive K+ channels (KATP channels), or vehicle was infused into the lateral ventricle in the basal state and during hyperinsulinemic-euglycemic conditions in postabsorptive, chow-fed C57Bl/6J mice and in postabsorptive C57Bl/6J mice with dietinduced obesity. Whole-body glucose uptake was measured by D-[14C]glucose kinetics and tissue-specific glucose uptake by 2-deoxy-D-[3H]glucose uptake. RESULTS - During clamp conditions, intracerebroventricular administration of tolbutamide impaired the ability of insulin to inhibit EGP by ~20%. In addition, intracerebroventricular tolbutamide diminished insulin-stimulated glucose uptake in muscle (by ~59%) but not in heart or adipose tissue. In contrast, in insulin-resistant mice with diet-induced obesity, intracerebroventricular tolbutamide did not alter the effects of insulin during clamp conditions on EGP or glucose uptake by muscle. CONCLUSIONS - Insulin stimulates glucose uptake in muscle in part through effects via KATP channels in the central nervous system, in analogy with the inhibitory effects of insulin on EGP. Highfat diet-induced obesity abolished the central effects of insulin on liver and muscle. These observations stress the role of central insulin resistance in the pathophysiology of diet-induced insulin resistance. © 2011 by the American Diabetes Association.