Inhibitors of Proteolysis and Glucose Uptake by Diaphragm Muscle In Vitro under Insulin Action

Abstract

Pieces of rat diaphragm, incubated for determination of insulin action upon their glucose uptake, release proteolytic activity in the medium and, after one hour, 90 percent of the original immunoreactive insulin has disappeared. Kunitz's and Soja bean inhibitors reduce by half this degradation, thus allowing determination of insulin concentrations in the physiological range. The results obtained suggest a rapid turnover of insulin at its receptor site. Kinetics of insulin specific binding at equilibrium and of its biological action upon in vitro glucose uptake cannot be compared.

Key words

Insulin - Diaphragm Muscle - Proteases - Biological Action