The distribution of 3-hydroxy-3-methylglutaryl coenzyme A reductase in the small intestine of rats fed raw or gelatinized starch as a carbohydrate source.

The effect of gelatinization of dietary starch (wheat, corn and potato) on the distribution of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase along the small intestine of rats was studied in villus and crypt cell populations isolated by graduated scraping. Gelatinized starch preferentially stimulated jejunal reductase activity in both villus and crypt cells and consequently retained the ileojejunal gradient for the reductase activity which is characteristic for rats fed on a sucrose- or glucose-enriched semi-purified diet. The distribution of the reductase in rats fed the raw starches, however, depended on the degree of gelatinization of the preparations; raw wheat starch maintained the ileojejunal gradient, whereas the corn or potato starch eliminated the gradient, and with the latter in particular, the reductase activity tended to be higher in the ileum than in the jejunum. The digestibility of dietary starches seems to be closely related to the intertissue distribution of the intestinal HMG-CoA reductase activity.