Determinants of postabsorptive endogenous glucose output in non-diabetic subjects

Abstract

Aim/hypothesis. To gain insight into the physiologic determinants of postabsorptive endogenous glucose output (EGO) in humans. Methods. We analysed the data of 344 non-diabetic subjects (212 men and 132 women) with a wide range of age (18-85 years) and body mass index (15-55 kg/m2) who participated in the European Group for the Study of Insulin Resistance (EGIR) project. Whole-body endogenous glucose output was measured by tracer ([3H]glucose) dilution at steady-state, peripheral insulin sensitivity (δ glucose clearance/δ insulin) was measured by the euglycaemic insulin (7 pmol x min-1 x kg-1) clamp technique. Results. Whole-body endogenous glucose output showed a large variability (mean = 768 ± 202 μmol · min-1, range 209-1512) and was strongly related to lean body mass (r = 0.63, p < 0.0001). This association entirely explained the endogenous glucose output being higher in men than in women (827 ± 189 vs 674 x 187 μmol x min-1, p < 0.0001), its relation to body mass (+ 10 ± 2 per unit of body mass index, p < 0.0001) and its trend to decline with age (-1.1 ± 0.7 μmol · min-1 per year, p = 0.10). Although inversely related to one another (r = -0.41, p < 0.0001), peripheral insulin sensitivity and fasting plasma insulin were both independently associated with endogenous glucose output in an inverse fashion (with partial r's of 0.19 and 0.21, respectively, after adjusting for lean body mass and centre, p < 0.0001 for both). Conclusion/interpretation. Among non-diabetic subjects in the postabsorptive condition, total body endogenous glucose output variability is wide and is largely explained by the amount of lean mass; this, in turn, explains differences in total endogenous glucose output due to sex, obesity and age. Independently of the amount of lean mass, peripheral insulin resistance is associated with a higher endogenous glucose output independently of fasting plasma insulin concentration, suggesting coupled regulation of insulin action in peripheral tissues and the liver.