Figure 2.

Schematic diagram of the extended combined model that accounts for the kinetics of endogenous insulin and C‐peptide, in addition to exogenous insulin. Insulin and C‐peptide are assumed to be secreted by β‐cells in an equimolar fashion (i.e. S[t]). A fraction, F, of the secreted insulin survives hepatic transit, appears in the systemic circulation and is distributed within the single plasma compartment. All of the C‐peptide survives hepatic portal transport and is assumed to follow two‐compartment distribution kinetics. The injected insulin goes through two compartments before being distributed into the plasma compartment along with the endogenous insulin.