Inhibition of sucrase by tris in rat and man, demonstrated by oral loading tests with sucrose

In the course of work concerned with the inhibition of small intestinal carbohydrate digesting enzymes, experiments were performed on rats and two healthy volunteers using tris as a sucrase inhibitor. The following results were obtained: (1) Tris does not lower the blood glucose in fasting rats after oral or subcutaneous doses up to 500 mg/kg, when administered as neutral solution (pH 7.0). (2) Tris reduces reduces the glycemia in rats and human subjects after a sucrose load. In addition, the insulinemia caused by administration of sucrose is reduced in man. This smoothing effect on both curves is dose-dependent. A delay of gastric emptying by tris could be excluded. (3) After a glucose or matose load in rats, tris has no effect on the blood sugar curve. (4) The marked smoothing effect of tris is after sucrose loading is probably caused by its well-known in vitro inhibitory effect on intestinal sucrase activity of pigs and humans.