Date of Award
Doctor of Philosophy
Food and Nutrition
Dietary and insulin-deficiency types of hyperlipidemia were compared in adult normal and streptozotocin-induced diabetes in male breeder rats. Experimental diets--high-beef tallow (BT; 38% of calories as beef fat and 2% as corn oil), high-corn oil (CO; 40% corn oil) or low-fat (LF; 2% corn oil)--were fed ad libitum for two months. To accentuate effect of type of fat, a group of normal rats was fed first BT diet for two months and then switched to CO diet (NCO) for another two months; the reverse switch was done with an additional group of normal rats (CO to BT; NBT). In all animals, glucose and insulin were measured in plasma, and phospholipids (PL), total cholesterol (TC), free cholesterol (FC), cholesteryl ester (CE), triglycerides (TG) and apoproteins in very low density (VLDL), low density (LDL) and high density (HDL) lipoproteins;Normal rats consumed the same amount of energy per day but average weight gain was higher in BT and CO than LF rats. Dietary treatment did not affect plasma glucose or insulin; VLDL-, LDL-, or HDL-PL; TC or CE in VLDL, LDL or HDL; VLDL- or LDL-FC; VLDL- or HDL-TG; LDL- or HDL-total protein or VLDL-apo-E. HDL-FC was higher in CO and LF than BT rats. LDL-TG was lower in CO and LF than BT rats. A dietary change from CO to BT (=NBT) resulted in a marked elevation of TG, with NBT similar to diabetic rats. VLDL-apo-B was lower in LF than BT rats. Feeding high-fat diets for four compared to two months resulted in an increase in apo-E and decrease in apo-C. In LDL, apo-B was lower and apo-E higher in LF-than high-fat-fed rats. HDL-apo-E was higher and HDL-apo-Al lower in LF- than high-fat-fed rats. HDL-apo-C was higher in LF than NCO rats;Compared to normal rats, total LDL- or HDL-protein or VLDL-CE were not affected in diabetic rats. Diabetic rats had higher plasma glucose, VLDL-TC and FC, VLDL-TG, LDL-apo-B, HDL-apo-B and HDL-apo-C levels and lower plasma insulin, LDL- and HDL-TC and CE, HDL-FC, LDL- and HDL-apo-E levels than normal rats. LDL-TG were higher in diabetic than all normal except NBT rats. VLDL-apo-B was lower in LF than diabetic rats. HDL-apo-Al was higher in diabetic than CO and LF but not BT rats. The results related to lipoprotein composition support the hypothesis that excess intake of a diet high in saturated fat may contribute to a metabolic pattern which resembles that of a diabetic state.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Hennig, Bernhard, "Lipoprotein lipid and protein responses to dietary fat and diabetes in rats " (1982). Retrospective Theses and Dissertations. 8350.