Effects of Trypsin and Chymotrypsin on Blood Glucose in vivo and Glucose Uptake in vitro . ∗

Summary

Experiments have been undertaken to extend the observation of Rieser and Rieser that chymotrypsin and trypsin have insulin-like activity in vitro(1) and that insulin has some protease properties(2). Concentrations of trypsin and chymotrypsin equal to molar concentrations of insulin which cause a marked hypoglycemia in vivo were administered to rats and dogs. Neither trypsin nor chymotrypsin had any insulin-like activity in vivo. These enzymes were also tested on the in vitro glucose uptake of rat hemidiaphragms and epididymal fat pads. Only trypsin had a marginal effect on glucose uptake, an effect that was much less than the effect of an equimolar concentration of insulin.