Role of the dopaminergic receptors D1 and D2 in the rapid-onset behavioural sensitisation to modafinil

The purpose of this study was to determine blood and liver lipid responses in rats to stepwise replacement of palm oil with high-stearate and high-oleate lipids with and without dietary cholesterol. Two 28-day experiments were conducted in which 12% fat (wtwt) was fed to rats in diets containing 0 (EXP1) or 0.4% cholesterol (EXP2). Nine diets were compared in each experiment: 12% palm oil was replaced in 3% increments by a high-stearate lipid (five treatments); 6% palm oil combined with 6% high-oleate safflower oil, 12% high-oleate safflower oil, 12% tallow, and 12% corn oil. Gain: consumption ratios were lower when rats were fed high-stearate fats. Plasma and liver cholesterol were greater when rats were fed 0.4% cholesterol (EXP2 compared with EXP1). The tallow diet produced the lowest plasma cholesterol in EXP1, but the highest level in EXP2. Similar plasma cholesterol levels, occurred for groups fed 12% palm oil, corn oil, and saffower oil, with or without dietary cholesterol. In EXP1, dietary treatments had little effect on liver cholesterol. In EXP2, liver cholesterol decreased as consumption of the high-stearate fat increased, and was highest with 12% saffower oil. Proportions of hepatic fatty acids generally reflected intake; however, greater (16:1 and 18:1) and lower (18:0 and 20:4) occurred in cholesterol-supplemented rats (EXP2 compared to EXP1). In conclusion, rat plasma and liver lipid responses to different dietary fats are affected by dietary cholesterol, the presence of which greatly increases liver cholesterol, liver total fat, and tallow-induced hypercholesterolemia.