• Preventive Nutrition and Food Science
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• v.16 no.4
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• pp.283-290
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• 2011

The recent increase of colon, breast, and prostate cancer incidence in Korea has been attributed to a diet pattern change to a more Western style, in which the foods eaten are higher in protein and fat. Whether high protein intake itself stimulates tumor cell growth and exacerbates disease status has been investigated, however, many epidemiological studies have inconsistent results between meat intake and the risk of certain cancers. These inconsistent results are partly because of the difficulty of studying the effects of just the meat intake. Other factors, such as overall meal context, could not be completely excluded in the study. To address the question of whether high protein itself is independently associated with carcinogenesis, we initiated ICR mice with 200 nmol ($50{\mu}g$) 7,12-dimethylbenz[a]anthracene (DMBA) and fed animals either a normal diet (ND, 14% casein) or a high protein diet (HPD, 50% casein) for 15 weeks with 12-O-tetradecanoylphorbol-13-acetate (TPA) promotion in two-stage skin carcinogenesis protocol. There was no significant difference between ND and HPD group in food intake and body weight throughout the experiment. However, tumor multiplicity of the HPD group was decreased by 75.5% compared to that of the ND group. In addition, HPD inhibited skin hyperplasia and epidermal cell proliferation. Western analyses with whole skin lysates showed that HPD inhibited TPA-induced Akt (S473), S6K (T389), 4E-BP1 (Thr 37/46) and Erk1/2 (Thr202/Tyr204) phosphorylation as well as COX-2 expression. Taken together, these data suggest that a high protein diet has an anticarcinogenic effect by inhibiting the TPA-induced Akt signaling pathway.

• Journal of Nutrition and Health
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• v.24 no.3
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• pp.149-156
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• 1991

To determine the effect of dietary fat and calorie level on protein kinase C(PKC) activity in mouse epidermal cells, female BALB/C mice (4weeks of age) were placed on high (24.6% ), moderate(5%) fat or calorie-restricted diets for at least 4 weeks. Diets were formulated on a nutrient/kcal basis such that the mice consumed the same amounts of protein. vitamins, minerals and fiber per kcal. PKC was assayed by the procedure of Wise et at. An apparent increase of PKC activity was observed from the aminal fed high fat diet when compared with the aminal fed moderate fat diet. PKC activity was decreased 40% by calorie restriction. In summary levels of dietary fat may contribute to mechanism of tumor promotion by increasing PKC activity in the mouse skin model.

• YAKHAK HOEJI
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• v.22 no.2
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• pp.72-82
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• 1978

This study was undertaken establish the relationship between trypsin inhibitor in raw soybean and antinutritional effect of raw legumes. 1) Among legumes produced in Korea, Glycine max contains a relatively high amount of protein(higher than 40%) compared with kindey bean, sword bean and mung bean and, furthermore, soybean which contains a high amount of protein possesses high trypsin inhibitory activity. 2) Disc electrophoretic pattern exhibited pattern exhibited that the crude protein preparation from Glycine max produced about 9-12 protein bands, and the pattern of electrophoretic mobility was very similar to each other. However, only a few protein bands were observed from the crude protein preparation of yard long bean, sword bean, adzuki bean, mung bean and rice adzuki. From the eluate of the sliced gel, it was confirmed that among those bands, only the fastest moving band contains trypsin inhibitory activity. 3) In chicks fed the normal diet the body weight was increased steady from one week and reached to 40% increase for three weeks but in chick fed raw bean diet, there was no body weight gain until two weeks feeding and only 10-20% of body weight gain was observed at the end of three week feeding. On the other hand, in chicks fed raw bean diet the weight of pancreatic tissue per 100g body weight was increased to about two-fold for two or three weeks but there was no change in liver weight. 4) In the case of amylase secretion from the pancreatic fragment, very strong stimulation on amylase secretion from pancreatic tissue of chicks fed a normal diet was produced by one unit of cholecystokin-pancreozymin. However, no stimulation was observed from pancreatic fragment of chick fed raw bean diet.

• Journal of Nutrition and Health
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• v.14 no.3
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• pp.136-145
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• 1981

This study was designed to observe the effects of both control and atherogenic diets on the cholesterol and triglyceride (TG) in serum and liver of adult rats fed diets supplying two levels of dietary fat and two different sources of dietary protein in early life. For the first experimental period, the rats were assigned into the four diet groups: High fat, casein (HC); High fat, gluten (HG); Low fat, casein (LC): Low fat, gluten (LG). Each group was subdivided into control and atherogenic groups for the second experimental period. Cholesterol and TG were determined in serum and liver after 7 hr fasting. The body weight gain was greater in the rats of the casein groups than those of the gluten groups tut not influenced by the level of the dietary fat. The difference in body weight from the quality of dietary protein in the first period was not disappeared even after the second period. After the first period, higher serum cholesterol was observed in the rats fed either casein or high fat diets. With the second experimental diet, rats fed atherogenic diet showed higher serum cholesterol concentration but lower serum TG levels compared to those fed control diet, regardless the diets fed in the first period. Serum cholesterol level of the rats of both groups which had been fed high fat diets in early life was increased compared to those of the low fat diet groups. This effect was more pronounced with the atherogenic diet groups than control groups. However, no differences were found in serum cholesterol levels resulted from the different types of dietary protein fed in the first period. Serum TG concentration was not influenced by the quality of protein and level of fat in the diet but seemed to be mere affected by the amount of carbohyrates in the diet. Liver cholesterol per unit weight was greater in the gluten diet groups than in the casein groups but total cholesterol was higher in casein fed rats. There were no differences in liver TG among the groups.

• Journal of Nutrition and Health
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• v.30 no.6
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• pp.605-613
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• 1997

This study was to investigate interaction between dietary protein and Ca levels in Ca metabolism and renal function in osteporosis rats. Five week-old female rats were fed a low Ca diet for 4 weeks after ovariectomy operation to establish rat models of osteoporosis. The ovariectomized osteoporosis rats were divided into six groups and were fed experimental diets which contained two levels of protein, normal (20%) and high(40%) , and three levels of Ca, low (0.06%), normal (0.47%) and high(0.94%) for 4 weeks , respectively. The ovaricetmized rat model of osteoporosis showed a remarkable decrease in serum Ca concentration, fresh weight and breaking force of femur, Ca and P contents of femur, and apparent absorption and retention of Ca. The supplementations of Ca and P contents of femur, and apparent absorption and retention of Ca. The supplementations of Ca at the dietary levels of normal and high levels significantly enhanced Ca bioavailability shown in the above experimental rat models of osteoporosis, regardless of dietary protein levels ; whereas the rats which were fed the low Ca diet demonstrated rather a decrease in its bioavailability. Irrespectively of the dietary Ca levels, the rats which were fed high protein diet exhibited an increase in kidney weight, urinary Ca, volume and hydroxyproline, and glomerular filtration ratio(GFR). The results show that dietary protein and calcium levels affect the renal function and Ca metabolism independently, while the interaction between protein and calcium have not been shown.

• 한국체육학회지인문사회과학편
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• v.54 no.2
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• pp.431-439
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• 2015

The purpose of this study was to investigate the effects of resistance exercise training and high-protein diet on anabolic factors and insulin resistance of skeletal muscle in sarcopenic obese rats. 50wks of male Sprague-Dawley rats were randomly assigned for 4 groups(Chow, HP, Ex, HPEx) after 6 weeks of high-rat diet induced obesity period. The 8-week of ladder climbing exercise significantly reduced body fat and insulin resistance, significantly increased mTOR activity. However hind limb muscles weight were not changed. When treat with exercise and high-protein diet, body fat and insulin resistance did not improve, but rather the effect of exercise training appeared to be inhibited. Therefore high protein diet for improving the sarcopenic obesity may be need more study about the amount and composition of protein.

• Journal of Nutrition and Health
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• v.28 no.5
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• pp.415-425
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• 1995

This study was performed to investigate the effect of dietary protein level on the metabolic changes of Ca and skeletons in postmenopausal women, using ovariecotomized rats as an animal model. The female rats of 200∼250g were fed either 8%(L) or 50%(H) casein diet for 15 weeks(1st experiment). At 15th week, the rats of each diet group were undergone ovariectomy or sham-operation and they were continued to feed the same experimantal diet for 9 more months(2nd experiment). Ca metabolism, kidney function and bone composition were determined at the end of 1st experiment, 3rd and 9th month of 2nd experiment. After 1st experiment, high protein group showed higher urinary Ca and protein excretion, however, there was no difference in GFR and urinary hydroxyproline excretion. The weights, ash and Ca content of femur, scapular and vertebra tended to be higher in high protein groups which tells that high protein promoted skeletal growth. In 2nd experiment, high protein group showed higher urinary Ca and protein excretion and lower Ca absorption and balance. GFR was not affected by dietary protein and ovariectomy but increased with time, as well as kidney weight which shows the continuous development of kidney at this age of 15 month in rats. There were no difference in urinary hydroxyproline, serum ALP, and PTH among experimental groups. The weights of femur, scapular, 4th vertebra increased with time, showing the skeleton continues to grow at this age in rats. However, Ca contents, Ca/wt, Ca/ash were decreased with time and tended to be lower in high protein group especially in femur. In conclusion, prolonged feeding of high protein diet deteriorated Ca metabolism and induced bone loss as time after menopause is extended.

• Proceedings of the KSCN Conference
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• 2004.05a
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• pp.437.1-437
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• 2004

The protein, called PTP1B (protein tyrosine phosphatase 1B), joins a list of enzymes that mice are associated with obesity. The purpose of this study was to investigate the effects of PTP1B inhibitors and taurine on blood lipid profiles in adolescents obesity model rats. Three week-old thirty-six male Sprague-Dawley rats were randomly assigned to six groups (high fat diet group; HFD group, high fat diet ＋ taurine group; HF＋TR group, high fat diet＋PTP1B inhibitor A group; HF＋A group, high fat diet＋PTP1B inhibitor B; HF＋B group, high fat diet＋PTP1B inhibitor A＋taurine group; HF＋A＋TR group, high fat diet ＋ PTP1B inhibitor B＋taurine group; HF＋B＋TR group).(omitted)

• Journal of Nutrition and Health
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• v.10 no.1
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• pp.10-17
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• 1977

This study was designed to compare the Biological effects of the cereals and legumes Proteins on albino rats. Fifty weaning albino rats weighing $49\;gr{\pm}2$ in both sexes were divided into 5 groups and fed corn crude protein diet, wheat crude protein diet, soybean protein diet, yeast diet and 30% sugar-casein diet for the control group. The protein contains same levels with isocaloric values each diet. After 12 weeks the rats were sacrificed for chemical analysis and the results are as follow ; 1. The highest food consumption was found in the groups of yeast and soybean, and the lowest was found in the groups of wheat diet and corn diet. 2. The groups of yeast & soybean protein showed the highest body weight increase, while the groups of wheat diet and corn diet showed the lowest. 3. Highly significant difference was found between the standard group and the groups of corn protein and soybean protein in Food Efficiency Ratio. (F. E. R.) (p<0.01). 4. Protein Efficiency Ratio showed a similar pattern as the F.E.R., however, there was no significant differences among the groups. 5. The kind of diets did not influence the hematology of the subjects. 6. The rate of nitrogen retention of male standard group was lower compared with all the experimental groups (p<0.01), and that of female soybean group was higher than any other groups (p<0.01). 7. Female corn diet group had the lowest organ weights, as found in the growth rate, which was significant (p<0.01). In the male corn diet group only the kidney showed significantly low in weight (p<0.01), and the spleen of male yeast group was also shown low with significance (p<0.01). 8. Nitrogen retentions of the liver and muscle in male corn diet group were lower than any other groups (p<0.05), and the brain nitrogen content of female standard group was high with significance (p<0.01). According to the results above, yeast and soybean protein can be regarded as a nutritious and also inexpensive protein sources.

• Fisheries and Aquatic Sciences
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• v.24 no.3
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• pp.109-120
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• 2021

Protein hydrolysates and krill meal (KM) are used as protein sources in aquafeeds. The study was conducted to examine the supplemental effects of shrimp protein hydrolysates (SH) or KM in a high-plant-protein diet for red seabream (Pagrus major). A fish meal (FM)-based diet (40%) was considered as the high-FM diet (HFM) and a diet containing 25% FM and soy protein concentrate, in the expense of FM protein from HFM diet, was considered as the low fish meal (LFM) diet. Two other experimental diets (SH and KM) were prepared by including SH and KM into LFM diet at 5% inclusion levels in exchange of 5% FM from the LFM diet. A feeding trial was conducted for fifteen weeks using triplicate group of fish (Initial mean body weight, 8.47 ± 0.05 g) for a diet. Growth performance and feed efficiency of fish were significantly enhanced by HFM, KM and SH supplemented diets over those of fish fed LFM diet. Interestingly, these parameters of fish fed SH diet showed better performance than KM and HFM groups. Liver IGF-I expression of fish fed SH diet was comparable to HFM group and higher than KM and LFM diets. Protein digestibility of SH diet was significantly higher than KM, HFM, and LFM diets. Dry matter digestibility of SH diet was comparable to HFM diet and significantly higher than KM and LFM diets. Nitro blue tetrazolium and superoxide dismutase activities of HFM, SH and KM groups were significantly elevated than the LFM group and SH diet increased catalase and glutathione peroxidase activities of fish compared to KM and LFM groups. Hemoglobin level and hematocrit of fish fed SH and KM diets were significantly higher than LFM group. A diet containing 20% FM with KM is comparable to a HFM diet which contains 40% FM for red seabream. SH can be used to replace FM from red seabream diet down to 20% and fish performance can be improved better than a diet containing 40% FM. Overall, it seems that SH is more effective ingredient in red seabream diet compared to KM.