Abstract

Radioactive iodine has been used for labelling insulin by coupling diazotized radioactive iodoaniline to insulin. The absorption rate of radioactive insulin injected subcutaneously was compared with its absorption rate from two depot insulin preparations by measuring the decrease of radioactivity at the site of the injection. A correlation was found to exist between the differences in the absorption rate and the differences in the intensity of hypoglycemic action produced by the preparations studied. The rate of the absorption of insulin from these preparations was found to be in the following order: insulin > globin insulin (with zinc) > protamine zinc insulin.