Plasma Insulin and C-peptide in Normal and Glucose Intolerant Males: the Role of Hepatic Insulin Uptake

. Plasma immunoreactive insulin and C-peptide were measured in the basal and glucosestimulated state in middle-aged males. Normals were compared with individuals with mild to moderate glucose intolerance. The results demonstrate the value of C-peptide measurements in the assessment of “true” insulin secretion and suggest that a reduced hepatic insulin extraction is a feature of the glucose intolerant state.