Regional disposal of intravenously infused glucose during prolonged hyperglycemia-hyperinsulinemia

We measured splanchnic and leg glucose uptake during prolonged (i.e., 15 ho urs), moderate hyperglycemia-hyperinsulinemia (clamp). Plasma free fatty ac id (FFA) concentration was maintained at basal concentration during the cla mp via infusion of exogenous lipids and heparin in healthy volunteers to cr eate a metabolic profile similar to glucose intolerance (i.e., hyperglycemi a-hyperinsulinemia with elevated FFA concentration). During the clamp, gluc ose was infused at an average rare of 49 +/- 4 mu mol/kg/min, which resulte d in a plasma glucose concentration of 8.8 +/- 0.5 mmol/L compared with a c oncentration of 4.4 +/- 0.2 mmol/L in the basal state (P < 005). Insulin co ncentration increased from 5.5 +/- 1.1 mu U/mL (basal) to 31.3 +/- 12.7 mu U/mL (clamp; P < 0.05), whereas plasma FFA concentration was similar in the two conditions (3.9 +/- 0.5 mmol/L and 4.1 +/- 0.5 mmol/L, basal and clamp , respectively). Glucose balance across the splanchnic region switched from net release (-5.8 +/- 0.7 mu mol/kg/min) in the basal state to net uptake in the clamp (19.8 +/- 3.7 mu mol/kg/min; P < 0.05) and accounted for appro ximately 40% of the infused glucose. Glucose uptake across the leg was 0.7 +/- 0.2 mu mol/kg/min (basal) and 5.5 +/- 2.2 mu mol/kg/min (clamp; P < 0.0 5). In summary, tissues in the splanchnic region (i.e., liver) are importan t for disposal of intravenously infused glucose during prolonged, moderate hyperglycemia-hyperinsulinemia. Accelerated hepatic glucose uptake may disr upt normal liver metabolism, with potentially dangerous consequences for th e patient. Measures to control systemic glucose concentration may be necess ary to prevent excessive glucose disposal in the liver. (J. Nutr. Biochem. 10:547-554, 1999) (C) Elsevier Science Inc. 1999. All rights reserved.