Effects of Blood Glucose Concentration on Thermogenesis and Glucose Disposal during Hyperinsulinaemia

Abstract

1. The thermogenic and cardiovascular responses to glucose ingestion or infusion are altered by undernutrition. These changes may be due, in part, to alterations in the blood glucose concentration. This study investigates the effect of variation in the blood glucose concentration on the thermogenic and cardiovascular responses to a hyperinsulinaemic glucose clamp. 2. Ten healthy post-absorptive subjects (six male, aged 21-30 years) were studied on two occasions. Baseline measurements were made for 30 min, followed by a 90 min continuous insulin infusion (100 m-units min-1 m-2), during which the arterialized venous blood glucose concentration was maintained at 4.5 mmol/l (euglycaemia) or 3.5 mmol/l (mild hypoglycaemia). Measurements were made of glucose infusion rate and respiratory gas exchange from which glucose storage and oxidation and metabolic rate were calculated. 3. During the final 30 min of each hyperinsulinaemic clamp, the rates of glucose disposal (53.5 +/- 1.4 versus 38.2 +/- 1.0 mumol min-1 kg-1, P less than 0.01) and glucose storage (32.4 +/- 1.1 versus 22.8 +/- 1.2 mumols min-1 kg-1, P less than 0.05), and the increase in metabolic rate (0.44 +/- 0.08 versus 0.11 +/- 0.09 kJ min, P less than 0.01), were all greater with a blood glucose concentration of 4.5 mmol/l than of 3.5 mmol/l.(ABSTRACT TRUNCATED AT 250 WORDS)