Original Article -Cell Function in Morbidly Obese Subjects During Free Living

Insulin hypersecretion and insulin resistance are phys-iologically linked features of obesity. We tested whether extreme hypersecretion impairs -cell function under free-living conditions and whether major weight loss modifies insulin hypersecretion, insulin sensitivity, and -cell function. Plasma glucose, C-peptide, and free fatty acid concentrations were measured at hourly in-tervals during 24 h of normal life (including calorie-standardized meals) in 20 morbidly obese nondiabetic patients (BMI 48.4 1.7 kg/m2) and 7 nonobese age-and sex-matched control subjects; 8 of the obese pa-tients were restudied 6 months and 2 years following biliopancreatic diversion. Insulin secretion was recon-structed from C-peptide levels by deconvolution and related to concurrent glucose levels through a mathe