RELATIONSHIPS BETWEEN GLUCOSE-METABOLISM AND THERMOGENESIS WITH AND WITHOUT PRIOR EXERCISE IN OBESE WOMEN WITH NON-INSULIN-DEPENDENT DIABETES-MELLITUS

The rate of insulin-stimulated glucose disposal is reduced in individu als with insulin resistance, and is associated with a blunted or absen t increase in energy expenditure in response to a glucose load. The ma gnitude of the effect of glucose on energy expenditure (EGEE) may be a function of opposing changes in the rate of glucose disposal (Rd) and hepatic glucose production (HGP). In this study, six women with non-i nsulin-dependent diabetes mellitus (NIDDM) were studied on a metabolic ward in each of three conditions. On days 1 and 2, they did no exerci se (NX) or else performed low-intensity exercise ([LO] 3,118 kJ [745 k cal]) at 50% maximal oxygen consumption [Vo(2)max]) or high-intensity exercise ([HI] 3,114 kJ [744 kcal] at 75% Vo(2)max). On day 3, infusio n of 6,6(2)4H-glucose in the basal state was immediately followed by i nfusion of glucose, 6,6(2)H-glucose, and insulin at fixed rates. Indir ect calorimetry was performed during the last 30 minutes of each infus ion. EGEE was not different among the three conditions (mean +/- SEM: NX -0.18 +/- 0.11, LO -0.08 +/- 0.05, and HI -0.08 +/- 0.07 kJ/min) an d was inversely related to steady-state plasma glucose concentration, a direct measure of insulin resistance (r =-.89, P <.05). EGEE was pos itively correlated with glucose Rd (r =.94, P <.001) and negatively co rrelated with HGP (r =-.98, P <.05). The data indicate that the glucos e effect on energy expenditure was slightly positive in the more insul in-sensitive individuals, but negative in the more insulin-resistant s ubjects. The EGEE appears to be determined by the relative balance bet ween energy required to store glucose and energy saved by suppression of glucose production. Copyright (C) 1996 by W.B. Saunders Company.