Effect of heated fat upon metabolism of 1‐¹⁴C‐acetate in the rat

Abstract

Groups of rats were prefed for 18 weeks with fresh or heated corn oil (≈5% nonurea adduct) at 10, 20 and 30% protein levels and at 10% protein+2% cellulose; 1‐14C‐sodium acetate was injected intraperitonially into each animal and the radioactivity was measured in expelled CO2 and also in the lipid fractions of liver. In the groups of rats fed 10% protein, one‐half of the administered radioactivity was found 50 min after acetate injection into rats fed fresh oil, whereas 90 min were required to reach the same level in rats fed heated oil. The same trend was found in all the groups of rats receiving different protein levels. The conversion of acetate to CO2 was significantly higher at a 10% dietary protein level than at the 20 or 30%, but there appeared to be no significant difference in the conversions at the 20 and 30% protein levels. However addition of 2% cellulose to the 10% dietary protein level significantly increased the conversion of the acetate to CO2 in rats fed heated oil. The livers of animals receiving heated fat diets had a higher lipid content, mainly triglyceride. When the liver lipids from rats fed fresh corn oil were separated by argentation thin layer chromatography, the bulk of the radioactivity was found in the saturated fractions. Monoene, diene and triene fractions from the liver lipid of rats fed heated oil had almost twice the radioactivity of those from fresh oil, suggesting the preferential utilization of acetate in the synthesis of these unsaturated fatty acids.

Influence of meal pattern and dietary fat on cholesterol metabolism in adult rats recovering from undernutrition

“…These data are not in agreement with reports that lipogenesis decreases with substitution of high for moderate concentrations of dietary protein (Yeh and Leveille, 1969;Govind et al, 1973). Diets used here, however, contained 20% fat as compared to 5 and 15% fat in the other studies.…”