• Journal of Nutrition and Health
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• v.15 no.2
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• pp.119-128
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• 1982

The effect of dietary protein on growth and lipid levels of plasma and liver was studied in weanling male rats fed diets differing protein sources and amino acid balance. Rats were devided into 9 experimental diets which were grouped into 3 categories ; 1) Simple protein category includes gluten-, soy protein isolate-, and casein-containing diet groups, 2) Supplemented category includes casein supplemented with methionine, soy protein isolate supplemented with methionine, and gluten supplemented with lysine and methionine, 3) Mixed protein category includes diet groups containing gluten (2/3), casein (1/3), soy protein isolate (2/3) and casein (1/3), and casein (1/3), soy protein isolate (1/3) and gluten (1/3). The experimental diets composed of 15% protein, 65.8% carbohydrate, 10% fat and 1% cholesterol. The body wt. gain and P.E.R. were greater in rats of supplemented and mixed protein groups than simple protein groups. No statistical differences were found in plasma cholesterol among gluten, soy protein isolate and casein groups. Consumption of diets supplemented with limiting amino acid to gluten or soy protein isolate reduced the plasma cholesterol level by 23.2% and 34.2% respectively. However there was no difference between casein and the supplemented casein groups. The mixed protein groups shows relatively high plasma cholesterol concentration and low liver cholesterol levels. On the other hand gluten group showed low plasma cholesterol and high liver cholesterol levels, which means body cholesterol pool may not have been changed by the dietary protein. Feeding soy protein meal and the supplemented soy protein isolate resulted in lower plasma cholesterol, plasma triglycerides, liver cholesterol and liver triglycerides levels. This hypolipidemic effect is considered to see unique to soy protein isolate. Rats in gluten and the supplemented gluten groups showed lower plasma protein levels and a tendency of fatty liver.

• Biomedical Science Letters
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• v.16 no.1
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• pp.19-24
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• 2010

We analyzed and compared the concentration of total cholesterol (CHOL), high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol and triglyceride (TG) in serum and the serum protein electrophoresis fractions of thyroid disease patients. In comparison with the average of reference, our data showed that the average concentration of CHOL, LDL cholesterol and TG in hyperthyroidism patients were decreased significantly, but HDL cholesterol was increased significantly. In hypothyroidism patients, CHOL, HDL cholesterol, LDL cholesterol and TG were all increased significantly. In comparison of the concentration of lipids in each patient to reference range, 28.3% of hyperthyroidism patients showed abnormally low level of total cholesterol. In the patients with hypothyroidism, the percentage of patients showed abnormally high level of CHOL, HDL cholesterol, LDL cholesterol and TG were 37.7%, 10%, 68.8% and 49.1%, respectively. In our studies of serum protein electrophoresis, the average of ${\alpha}_2$-globulin and $\gamma$-globulin in hyperthyroidism patients were increased and $\beta$-globulin was decreased significantly. In hypothyroidism patients, the average of $\gamma$-globulin was increased and $\beta$-globulin was decreased significantly. In comparison of protein fractions of each patient to reference range, 38.3% and 50.0% of hyperthyroidism patients showed abnormally high levels of ${\alpha}_2$-globulin and $\gamma$-globulin, but 73.3% of patients showed abnormally low level of $\beta$-globulin. In hypothyroidism patients, 70.4% of patients were abnormally decreased in $\beta$-globulin and 63.9% of patients were abnormally increased in $\gamma$-globulin. These data suggest that the concentrations of CHOL, HDL cholesterol, LDL cholesterol and TG are not critical data for clinical interpretation of hyperthyroidism, but the levels of them are useful for interpretation of hypothyroidism patients. Our results of serum protein electrophoresis suggest that the concentration of serum protein electrophoresis fractions can be useful to understand the thyroid disease.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.479-483
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• 1994

The effects of the different protein source on serum cholesterol levels were studied in SD strain male rats. Fish protein prepared by the method of SUZUKI from Alaska Pollack (Theragra chalcogramma) was compared with casein and soybean protein isolate. Each protein source was incoporated into a cholesterol-free diet in order to provide a protein level of 20% for 2 weeks. The result obtained are as followed: Concentration of total-cholesterol, LDL-cholesterol, total-cholesterol/HDL-cholesterol and triglyceride in rats fed with fish protein group were significantly lower than those of rats fed with casein and similar to those of rats fed with soybean protein. In addition, it was shown that the ratio of Lys/Arg and Gly/Met+Cys of fish protein was close to that of soybean protein.

• Journal of Nutrition and Health
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• v.27 no.1
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• pp.3-11
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• 1994

This study was carried out to examine how dietary protein and calcium levels in rats fed fat-enriched diet affect the total lipid and cholesterol contents of blood and tissues. Male Sprauge-Dawley rats weighing approximately 200g were fed six purified diets which contained 18%(w/w) beef tallow, 1% (w/w) cholesterol, two source of protein, casein or isolated soy protein (ISP) and three levels of dietary calcium, 0.1%, 0.4% and 1.0%, first, for four weeks, and second, for eight weeks. The contents of the total lipid, cholesterol and triglyceride in blood, liver, heart and feces were determined. After four weeks feeding serum lipid and cholesterol concentrations significantly decreased in rats fed 1.0% (w/w) level calcium, regardless of dietrary protein sources. After eight weeks, these concentrations were significantly lower in the rats fed soy protein than in casein-fed rats. As dietary calcium level increased serum and tissue lipid and cholesterol contents were decreased and fecal lipid excretion increased. It is concluded that hypolipidemic and/or hypocholesterolemic effects of soy protein and calcium were partly due to decrease in lipid absorption.

• Korean Journal of Poultry Science
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• v.22 no.1
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• pp.43-54
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• 1995

Effects of dietary protein sources and their amino acid compositions on the liver and plasma cholesterol levels in growing Single Comb white Leghorn male chicks were studied. A diet containing isolated soy protein (21% cp) was supplemented with 0.5% DL-methionine and 0.3% L-glycine. and another diet containing casein(21% cp) was supplemented with 1.5% L-arginine HCl, 0.4% DL-methionine. and 1.0% L-glycine. Plasma cholesterol level was markedly lower in groups force-fed the diets containing either soy protein or casein supplemented with amino acids compared to those found in birds fed corresponding diets without amino acids supplementation. The cholesterol lowering effect of the casein diet. when balanced with various supplemental amino acids appeared to be due to arginine instead of methionine or glycine. It is likely that amino acid balance rather than the composition of a specific amino acid is one of the major factors determining the effect of dietary protein sources on the blood cholesterol levels in chicks.

• Journal of the Korean Applied Science and Technology
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• v.3 no.1
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• pp.23-31
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• 1986

Several authors reported that vegetable proteins cause to decrease serum cholesterol and reported the effect of limiting amino acid balance in dietary protein on the blood component. This study was designed to observe growth rate and blood component in 1% cholesterol-fed male rats intake pure isolated soy proteins and methionine for 4 weeks. The diets were supplemented with either 20% casein or isolated soy protein as dietary protein sources and methionine as limiting amino acid of isolated soy protein and casein protein. The results were as follows; 1) The body weight gain was the greatest in casein groups. 2) Serum total cholesterol concentration was significantly increased by casein groups and slightly decreased by isolated soy protein groups. 3) Serum HDL-cholesterol concentration was significantly increased by isolated soy protein groups than control group. 4) Serum total lipid and triglyceride concentrations were significantly decreased by isolated soy protein groups than control group. 5) Serum glucose concentration was significantly increased by isolated soy protein plus 0.8% methionine than control group. 6) Serum total protein and albumin concentrations were significantly increased by all experimental diets groups than control group. Especially, casein groups were the most increased in all experimental diets groups.

• Journal of Nutrition and Health
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• v.27 no.1
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• pp.90-99
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• 1994

This study was carried out to examine how dietary protein and calcium levels in rats fed fat-enriched diet affect the total lipid and cholesterol contents of blood and tissues. Male Sprauge-Dawley rats weighing approximately 200g were fed six purified diets which contained 18%(w/w) beef tallow, 1% (w/w) cholesterol, two source of protein, casein or isolated soy protein (ISP) and three levels of dietary calcium, 0.1%, 0.4% and 1.0%, first, for four weeks, and second, for eight weeks. The contents of the total lipid, cholesterol and triglyceride in blood, liver, heart and feces were determined. After four weeks feeding serum lipid and cholesterol concentrations significantly decreased in rats fed 1.0% (w/w) level calcium, regardless of dietrary protein sources. After eight weeks, these concentrations were significantly lower in the rats fed soy protein than in casein-fed rats. As dietary calcium level increased serum and tissue lipid and cholesterol contents were decreased and fecal lipid excretion increased. It is concluded that hypolipidemic and/or hypocholesterolemic effects of soy protein and calcium were partly due to decrease in lipid absorption.

• Journal of Nutrition and Health
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• v.30 no.6
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• pp.614-621
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• 1997

The experiments were performed to investigate the effects of protein and protein hydrolysates on lipid metabolism in the hyperlipidemic/hypercholesterolemic rat model induced by feeding fat-enriched diet. In Except 1 male rats were fed four semi-purified high fat and cholesterol diets that contained different nitrogen source, casein(C), casein hydrolysate(CH), corn gluten(G) and corn gluten hydrolysate(GH), for 6 weeks. In Expt. 2 rats were fed high fat and cholesterol diet for 4 weeks to induce hyperlipidemia and hypercholesterolemia. Then the rats were divided into 4 groups and were fed the four kinds of above experimental diets for 4 weeks consecutively. The contents of total lipid , cholesterol and triglyceride in blood, liver and feces were determined. Serum lipid concentrations of CH, G and GH were significantly lower than that of C. Serum cholesterol concentrations of hydrolysate groups(CH and GH) were significantly lower than those of intact protein groups(C and G). Serum HDL -cholesterol concentration tended to increase by hydrolysate intake. The total lipid, cholesterol contents in liver showed similarity results as above. Fecal lipid excretions of CH, G, and GH groups were significantly higher than that of C group. These results indicate that hypolipidemic and /or hypocholesterolemic effect of corn gluten or protein hydrolysates were detected in the process of inducing hyperlipidemia by high-fat and cholesterol diet or after inducing hyperlipidemia.

• Journal of Nutrition and Health
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• v.7 no.1
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• pp.45-50
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• 1974

Biochemical studies such as growth rate, blood cholesterol and ascorbic acid contents in various organs of albino male rats were studied in the Garlic, Vitamin E, high and low protein diet fed groups. The results of this study were summarized as follows : 1) Either single 10% or 30% protein diet fed rats were not shown growth rate properly. In supplementation of Vitamin E or Garlic on 30% protein growth rate was a more increased than that of the 10% protein diet group. 2) The rate of food consumption of rats fed a 10% or 30% protein diet supplemented with Vitamin E and Garlic was more increased than that of the control Group receving 10% or 30% protein diet alone. 3) No essential difference was observed between the cholesterol level in blood of rats fed 10% protein diet supplemented with Vitamin E and Garlic and that of rats Receiving 10% protein diet alone. But the cholesterol level in blood of rats fed 30% protein diet supplemented with Vitamin E and Garlic was lower than that of control receiving 30% protein diet alone. 4) The Vitamin C contents in various organs of rats fed the diet supplemented with Vitamin E and Garlic seems to be a little higher than that of the control group fed the protein diet alone.

• Nutritional Sciences
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• v.9 no.2
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• pp.74-81
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• 2006

The present study examined the effect of soy isoflavones on lipid metabolism in growing female rats. Rats were randomly assigned to three different groups and provided experimental diets for 9 weeks. The experimental groups were classified into 1) a control group, 2) a soy protein isolate group: soy (+)) group and 3) a soy protein concentration group: soy (-)) group. Diets contained either casein or one of two soy proteins with (soy (+)) or without isoflavones (soy (-)). Serum triglyceride concentration showed no significant differences among the experimental groups. Serum total cholesterol concentration was significantly lower in both the soy (+) and soy (-) groups than in the control group and LDL-cholesterol concentration was significantly lower in the soy (+). Serum HDL-cholesterol concentration was significantly higher in the control group than in the soy protein groups but the HDL-cholesterol share rate in total cholesterol tended to be lower in the control group than in the soy protein groups, insignificant as it was. Hepatic IDL receptor mRNA level was significantly increased in the soy (+) group when compared to the other two groups to be 20% higher than the control group. In conclusion, soy protein isolate, soy protein rich with isoflavones reduced serum total cholesterol and LDL-cholesterol concentration and increased hepatic IDL receptor mRNA expression in growing female rats. Therefore, it is considered that the intake of soy isoflvones during puberty can be advantageous in terms of the long-tenn control of serum lipid.