Specific effect of the amount of dietary fat on esterase-1 (ES-1) activity of rat plasma.

The question addressed is whether the amount of dietary fat rather than that of carbohydrates or protein affects esterase-1 (ES-1) activity in plasma of rats. For this purpose, the effects on plasma ES-1 activity of replacement of dietary fat, by isocaloric amounts of either carbohydrates or protein were studied in male rats. In rats fed high-fat diets, corn oil induced higher plasma ES-1 activities than coconut fat. Plasma ES-1 activity was decreased by a decrease in fat intake. Replacement of fat by carbohydrates produced a similar decrease of plasma ES-1 activity as did replacement of fat by protein. Replacement of carbohydrates by protein did not significantly change plasma ES-1 activity. It is concluded that the amount of fat in the diet specifically influences ES-1 activity in plasma.