The absorption of insulin.

It is desirable to improve metabolic control in diabetics receiving insulin. Studies on insulin kinetics provide information that may be useful in the optimization of the injection scheme. Absorption has been measured using 125I-insulin as marker and counting the residual activity with a crystal detector. Plasma insulin has been measured (by radioimmunoassay) in the absence of insulin antibodies. The relationship between the rate of absorption and exogenous insulinemia was analyzed using a simple mathematical model. The time course of plasma insulin was calculated for various insulin preparations, including mixtures. The data suggest the significance of the injection site for the effect of insulin, e.g., a more rapid effect after injection into the abdominal subcutaneous tissue. The pattern of exogenous insulinemia in patients treated with insulin bears no resemblance to that in normal subjects. The calculated patterns of exogenous plasma insulin after injection of various preparations suggest that insulin therapy might be improved to obtain a better and more physiological metabolic control.