Proteolytic Inhibitors in Serum I. Effect of Food Intake and of Hypophysectomy

Summary Measurements of antitryptic and antichymotryptic activity of serum have been carried out employing casein proteolysis. The results led to the conclusion that only one entity is involved in these phenomena. Fasting for 6 days had no effect on the antitryptic activity of serum. Hypophysectomy resulted in a marked decrease in the antitryptic activity, reversible by injections of whole pituitary. Injections of crystalline growth hormone led to an increase in the inhibitory activity of serum of hypophysectomized rats. No direct effect of growth hormone on chymotrypsin was observed.