OXIDATIVE-METABOLISM IN INSULIN-TREATED GESTATIONAL DIABETES-MELLITUS

To investigate whether protein, carbohydrate, and fat metabolism was n ormalized in insulin-treated gestational diabetes mellitus (GDM), eigh t Hispanic women with GDM and eight healthy controls were studied at 3 2-36 wk of gestation and 6 wk postpartum. Net substrate utilization wa s measured using room respiration calorimetry. Exogenous substrate oxi dation was determined by C-13 recovered in breath CO2 from C-13-labele d leucine, glucose, and Hiolein. Women with GDM had higher 24-h oxygen consumption, carbon dioxide production, total energy expenditure, and basal metabolic rates than controls due to larger body mass. Adjusted for weight or fat-free mass, total energy expenditure, basal metaboli c rate, and basal and 24-h whole body net protein, carbohydrate, and f at utilization did not differ between insulin-treated GDM subjects and controls in pregnancy or postpartum. Oxidation of [C-13]leucine and [ C-13]glucose did not differ by group or pregnancy status. Recovery of exogenously administered [C-13]Hiolein, a biosynthetic triglyceride, a s breath (CO2)-C-13 was significantly lower in the GDM group antepartu m and postpartum (P = 0.02), indicating lower oxidation of exogenous t riglycerides in GDM.