Studies on the in vivo-action of leupeptin on the nitrogen retention in rats.

A daily s.c. injection of 0.5 mg leupeptin for 7 days does not influence the digestibility of food-N but seems to improve the N-retention. A daily injection of 1.0 mg leupeptin for 14 days is without influence on the digestibility of N, too, but the N-retention was decreased. At this leupeptin level the half-lives of intestinal proteins were prolonged. The data indicate the possibility to influence the N-retention using leupeptin.