Effect of Cycloheximide and Actinomycin D on the Dietary Induction of Intestinal Brush Border Enzyme Activities of Rats

Abstract

The activities of intestinal alkaline phosphatase [E. C. 3.1. 3.1.], sucrase (β-D-fructofrano-side fructohydrolase) [E. C. 3.2. 1.26.] and leucine p-nitroanilidase [E. C. 3.4. 11.2.] were equally enhanced within 4hr after single feeding of egg albumin to 4-day starved rats. They were maintained at the induced levels up to 12hr, followed by a gradual decrease. Single feeding of sucrose did not affect sucrase activity within 8hr, but gradually raised it later than 12hr.
The injection of cycloheximide diminished these dietary induction of enzyme activities to the levels in starvation. In starved controls, only sucrase activity was inhibited by actino-mycin D whose dose inhibited the incorporation of ³H-uridine into the mucosal homogenate. However, in feeding rats, the same dose of actinomycin D decreased all the induced enzyme activities below the levels in starvation without inhibiting the incorporation of ³H-uridine.
The effect of dietary protein on brush border enzymes seemed to be little in germ-free rats as compared with conventional animals.