Effects of Dietary Protein on Plasma Lipoproteins and Liver Lipids in Cholesterol-fed Rats

Abstract

The effects of casein and soybean protein on plasma lipoproteins, apoproteins and liver lipids in cholesterol-fed rats were studied. 1) The diet composition for the standard group was (%): casein 20, corn oil 5, vitamin mix. 1, salt mix. 4, choline chloride 0.2 and corn starch to 100%. The control diet contained 0.5% of cholesterol and 0.3% of sodium cholate and 5% of lard replaced for corn oil. In rats given a control diet, the concentration of total cholesterol was higher in VLDL and LDL and lower in HDL2, and the concentration of ApoC in VLDL, ApoE, ApoA-1 and ApoC in HDL2 and ApoE in HDL3 were lower than in the animals given a standard diet. On feeding the control diet, much cholesterol and triglyceride were stored in the liver. 2) In order to investigate the effects of qualities and quantities of proteins, the diets containing 5% of lard, 0.5% of cholesterol and 0.125% of sodium cholate was used. The concentrations of serum total cholesterol was 134.7, 108.5, 95.5 and 81.6mg/dl on the diets of casein 20%, casein 40%, soybean protein 20% and soybean protein 40%, respectively. Especially in rats fed soybean protein diets the concentration of triglyceride also decreased. On the pattern of polyacrylamide gel disc electrophoresis of serum lipoproteins, the percentage of

Effect of soybean protein on coprostanol production and cholesterol metabolism in cholesterol-fed rats.

“…We also reported that when a diet was used containing 0.5% of cholesterol, the concentrations of plasma and liver cholesterol were lower in rats fed soybean protein than in those fed casein and HDL-cholesterol levels were higher in the soybean protein group (6). These data indicated the anti-atherosclerogenic activity of the.…”

Effect of partial hydrolyzates of casein and soybean protein on serum lipoproteins and fecal neutral steroids.

“…The effect of dietary protein on plasma cholesterol level has also been reported in the recent years (1-3). We observed that in the cholesterol-fed rats, high casein and soybean protein diet decreased plasma and liver cholesterol concentrations and increased high density lipoproteins (4). The difference of amino acid composition was demonstrated (5-8) but the presence of another unknown factor is considerable.…”