Use of Ac-L-Tyr-PAB for estimating the activity of chymotrypsin in rats.

Pancreatic secretion in rats was assessed by measuring the amounts of p-aminobenzoic acid (PABH) excreted in urine after oral administration of Ac-L-Tyr-PAB, and by determination of enzyme activity in pancreas and faeces. 3 groups of 7 rats were kept on diets with casein as the main source of nitrogen without (control K0) or with two levels of trypsin inhibitor (K1 and K2). Two other groups were fed diets with 40 and 80% of casein substituted by raw soya bean protein and having trypsin inhibitor contents equivalent to those in diets K1 and K2.