Huber MP, Zelnick LR, Utzschneider KM, et al. - Researchers sought to determine the correlations of tubular secretory clearance with whole-body insulin clearance and sensitivity in a dedicated study of glucose and insulin metabolism. They conducted an ancillary, cross-sectional study of tubular secretion in the Study of Glucose and Insulin in Renal Disease. In 57 nondiabetic persons with chronic kidney disease and 38 persons without kidney disease, hyperinsulinemic-euglycemic clamps were performed. Plasma and 24-hour urine concentrations of endogenous solutes were determined mainly by the elimination of tubular secretion. Data reported that mean whole-body insulin clearance was 924 ± 228 mL/min. Each 20% lower estimated GFR was correlated with a 13 mL/min lower insulin clearance after adjustment for age, gender, Black race, fat and fat-free mass. Each 20% lower clearance of isovalerylglycine and xanthosine were linked to a 16 mL/min lower and 19 mL/min lower insulin clearance, respectively. Such findings emphasize the significance of tubular secretory pathways for insulin elimination but suggest that overall kidney function contributes only modestly to systemic insulin clearance.