In these experiments, exogenous biosynthetic human C-peptide was infused at varying rates (solid line). C-peptide concentrations were simultaneously measured in peripheral plasma. The infusion rates of C-peptide were then estimated by deconvolution of the C-peptide concentrations using a two-compartment model of C-peptide kinetics (dashed line). The close approximation of actual and model-derived estimates of C-peptide infusion rates indicates that this approach can be used to derive secretion rates of C-peptide and therefore insulin. Reproduced from ref. 4.