Prehepatic Insulin Production in Man: Kinetic Analysis Using Peripheral Connecting Peptide Behavior*

The prehepatic production of insulin in normal man was evaluated by kinetic analysis of connecting peptide (C-peptide) behavior in the plasma in men and women. Studies were performed during suppression of endogenous insulin secretion (induced by both fasting and exogenous insulin injection) as well as during stimulation of secretion (induced by oral glucose ingestion) and iv glucose injection. Least squares spline fitting of the C-peptide data...