• Asian-Australasian Journal of Animal Sciences
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• v.24 no.9
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• pp.1274-1281
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• 2011

Dietary protein restriction affects lipid metabolism in rats. This study was performed to determine the effect of a low protein diet on hepatic lipid metabolism and insulin sensitivity in growing male rats. Growing rats were fed either a control 20% protein diet or an 8% low protein diet. Feeding a low protein diet for four weeks from 8 weeks of age induced a fatty liver. Expression of acetyl-CoA carboxylase, a key lipogenic enzyme, was increased in rats fed a low protein diet. Feeding a low protein diet decreased very low density lipoprotein (VLDL) secretion without statistical significance. Feeding a low protein diet down-regulated protein expression of microsomal triglyceride transfer protein, an important enzyme of VLDL secretion. Feeding a low protein diet increased serum adiponectin levels. We performed glucose tolerance test (GTT) and insulin tolerance test (ITT). Both GTT and ITT were increased in protein-restricted growing rats. Our results demonstrate that dietary protein restriction increases insulin sensitivity and that this could be due to low-protein diet-mediated metabolic adaptation. In addition, increased adiponectin levels may influences insulin sensitivity. In conclusion, dietary protein restriction induces a fatty liver. Both increased lipogenesis and decreased VLDL secretion has contributed to this metabolic changes. In addition, insulin resistance was not associated with fatty liver induced by protein restriction.

• Nutritional Sciences
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• v.1 no.1
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• pp.3-7
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• 1998

The aim of the present investigation was to see whether an anabolic steroid, nandrolone phenylpropionate (NPP), exerts protienanabolic effects under such adverse nutritional conditions as protein deficiency and protein-energy malnutrition in male rats. feeding on a low-protein (8% casein) diet resulted in a marked reduction in body weight gain that was associated with reductions in body protein and protein content of gastrocnemius muscle. Administration of NPP (4 mg/kg body weight) did not alter muscle and body protein depletion induced by a low-protein diet. 50% food restriction caused reductions in body protein and in protein content of gastrocnemius muscle. These reductions were partially prevented by NPP (4 mg/kg body weight). Food restriction did not affect plasma concentration of corticosterone, insulin, or tetosterone plus dihydrotestosterone. On the other hand, neither plasma concentration of corticosterone nor insulin were affected by NPP. The present results show that anabolic steroids do not express anabolic effects under conditions of protein deficiency, but in protein-energy malnutrition, anabolic steroids exert their anabolic effects even in male rats.

• Journal of Nutrition and Health
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• v.6 no.3
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• pp.1-8
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• 1973

Metabolic responses to the protein-free, high-carbohydrate diet and subsequent food restriction on the same diet at the level of 50% and 75% has been studied on the adult albino rats. The energy source was either corn starch or sugar. In experiment I, adult male rats weighing $509{\pm}8g$ were divided into two groups 10 rats each. Rats fed on the stock diet served as a control. Rats of restriction group received a protein free diet until they reduced their weight down to 400g and continue on a protein-calorie restriction diet until they reduced their weight down to 300g. In experiment II, 28 adult male rats and the same numbers of female rats weighing $329{\pm}5g$ and $223{\pm}4g$ respectively were divided into four groups, 7 males and females in each. Rats fed on a stock diet were sacrificed at the point when others started a protein free diet. These were served as the control. The protein free group received a protein free diet ad libitum for 4 weeks. The 50% restriction group and 75% restriction group were fed on a protein free diet coupled with food restriction at levels of 50% and 75% respectively for 3 weeks. In the result of this study: 1. The rate of body weight changes was similar between the males and the females. Feeding protein free diet ad lib. initiated a rapid weight lost of approximately 25% and protein free diet coupled with food restriction showed 37-43% reduction of their initial weight. 2. There was no significant differences in the value of the N concentration in liver, spleen, brain and muscle between controls and experimental groups. 3. Rats fed on protein free diet showed 1/10 value of the control in the nitrogen excretion in urine. However female showed less N excretion than male. 4. Observing blood picture, the effects of protein depletion and calorie restriction were not appeared any remarkable changes. 5. There was no sign of fatty liver which might result from protein depletion and calorie restriction. 6. Following semi-starvation, FAO and HMP-DH total enzyme activity was reduced, but activity per unit weight was relatively stable.

• Journal of Animal Science and Technology
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• v.64 no.2
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• pp.330-342
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• 2022

We aimed to investigate candidate proteins related to long-term caloric restriction and feed efficiency in bovine longissimus dorsi muscle (LM). A total of 31 Korean native steers were randomly distributed to ad libitum (n = 16) or caloric restriction group (n = 15) to conduct two feeding trials for 13 mon. In the first trial (10-18 mon of age), steers were fed with 100% ad libitum (NE_g = 0.63 Mcal/kg) or caloric restriction (80% of the previous day's feed intake of ad libitum group). In the second trial (18-23 mon of age), the energy value of 100% ad libitum diet was 1.13 Mcal/kg NE_g and those in caloric restriction group diet was 0.72 Mcal/kg NE_g. At the endpoint of this experiment, in each group, 6 animals were selected with high (n = 3) or low feed efficiency (n = 3) to collect muscle tissue samples (6 animals/group). From muscle tissues of 23 mo of age, we excavated 9 and 12 differentially expressed (two-fold or more) proteins in a nutritional group and feed efficiency group using two-dimensional electrophoresis, respectively. Of these proteins, heat shock protein beta-6 was up-regulated in both the caloric restriction and the low feed efficiency group. In bovine embryonic fibroblasts, the mRNA expression of heat shock protein beta-6 increased after adipogenic differentiation, however, decreased after myogenic differentiation. Our data provide that heat shock protein beta-6 may be an adipogenic protein involved in the mechanism of caloric restriction and feed efficiency in the LM of the steer.

• Journal of Nutrition and Health
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• v.16 no.4
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• pp.263-272
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• 1983

Effects of dietary protein qualify, energy restriction, and subsequent rehabilitation were studied in the weanling rats. Rats were devided into the six experimental diet groups. Rats in AC (casein- containing diet ), AS (soyprotein-containing diet), and AG(gluten-containing diet) group consumed their diets ad libitum, and rats in PC, PS, PG groups were pair-fed in 60% of the of amounts eaten by corresponding rats in the AC, AS, AG groups, respectively. After 3 weeks of nutritional restriction, all rats were switched to the AC diet for 14 days. At the end of restriction period, body weight, weight gain, food intake, and FER were higher in casein- fed rats than other groups of rats. The differences were, however, disappeared with rehabilitation diet, except body weights which were not fully recovered until the end of experiment. The weights of liver, gastrocnemius muscle, kidney, small intestine, spleen, and lung were the highest in the casein group, and the lowest in gluten group at the end of restriction period. The recovery with rehabilitation diet were differ in different organs. The muscle and liver seemed to be the most affected organs by dietary protein quality and energy restriction. There were no differences in brain weights among the experimental groups during the restriction period, however, after 2 weeks of rehabilitation, rats in AC group showed lower brain weight compared to AC and AS groups, and the brain weight of PC group was lower than AC group. Protein contents in liver and muscle showed the same trends as their weights. Gluten-fed rats showed low serum protein concentration, but recovered fully with rehabilitation diet for 3 days.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.5
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• pp.368-378
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• 2001

This study was performed to investigate the effects of isolated soyprotein and salt (NaCl) restriction on the serum lipid and the kidney functions of streptozotocin-induced diabetic rats. Sprague-Dawley males of normal and streptozotocin-induced diabetic rats were raised for 6 weeds divided into 4 groups each according to protein sources and salt levels. The sources of protein were isolated soyprotein and casein. Salt levels tested were 0.1% (normal) and 0.01% (low). The results are summarized as fellows: kidney weight, blood glucose, hemoglobinAlc, GFR and urinary protein of diabetic groups were higher than those of normal groups. Isolated soyprotein lowered total lipids, triglycerides, and total cholesterol in serum and plasma angiotensin II concentration as well as alleviated kidney enlargement and GFR in diabetic rats. Salt restriction didn\\`t affect serum lipid level but decreased GFR and increased angiotensin If concentration. In conclusion, isolated soyprotein decreased serum lipids, plasma angiotensin II concentration, sidney enlargement and GFR, while salt restriction increased plasma angiotensin II concentration. The results suggest that isolated soyprotein and salt restriction seem to cause different effects on plasma angiotensin II concentration and that isolated soyprotein might be of value in the prevention of diabetic artherosclerosis and diabetic hypertension.

• Journal of Nutrition and Health
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• v.6 no.4
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• pp.23-36
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• 1973

This study was designed to compare the effect of dietary intakes on different quality protein & levels of caloric consumption supplemented by sugar at the level of 26% of total caloric intakes. 30 males and same number of females of Albino rats, aged 30-40 days were devided into following six groups, 5 rats each. ACO Group: Ad libitum, Casein, no sugar group ACS Group: Ad libitum, Casein, 26% sugar supplemented group RBO Group: 50% restriction,Bean, no sugar group RBS Group: 50% restriction, Bean, 26% sugar supplemented group RAO Group: 50% restriction, Anchovy, no sugar group RAS Group: 50% restriction, Anchovy, 26% sugar supplemented group The rats were kept in individual cage and given 6 different diet for 12 weeks. The result of this study were elucidated as follow. Body weight gained and organ weight showed no significant differences between sugar supplemented group and the others. It was noteworthy that the shrinkage of female sex organ supplemented by sugar in the diet showed lower degree than that of compared groups in this study. In other word, degree of shrinkage due to protein-caloric restriction was decreased by sugar supplementation. Nitrogen Metabolism and total nitrogen retention were not observed any significant differences between sugar supplemented group and the others. Dental caries showed higher incidence for sugar supplemented groups. Hematology and bone growth showed no differences in this study. The similar results on the metabolic effects concerned the above view Points were obtained in the different protein groups such as bean & anchovy as protein sources in the diet. Caloric restriction Produced a lower growth-rate, lower body weight and poorer long bone growth. But composition of bone ash, concentration of nitrogen, calcium and blood glucose, liver fats and liver water content maintenanced at the same levels of standard group.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3542-3546
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• 2014

Relationship between molecular freedom of amyloidogenic protein and its self-assembly into amyloid fibrils has been evaluated with ${\alpha}$-synuclein, an intrinsically unfolded protein related to Parkinson's disease, by restricting its structural plasticity through an end-to-end disulfide bond formation between two newly introduced cysteine residues on the N- and C-termini. Although the resulting circular form of ${\alpha}$-synuclein exhibited an impaired fibrillation propensity, the restriction did not completely block the protein's interactive core since co-incubation with wild-type ${\alpha}$-synuclein dramatically facilitated the fibrillation by producing distinctive forms of amyloid fibrils. The suppressed fibrillation propensity was instantly restored as the structural restriction was unleashed with ${\beta}$-mercaptoethanol. Conformational flexibility of the accreting amyloidogenic protein to pre-existing seeds has been demonstrated to be critical for fibrillar extension process by exerting structural adjustment to a complementary structure for the assembly.

• Journal of Nutrition and Health
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• v.14 no.4
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• pp.151-161
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• 1981

The objective of this study was to compare the electrolytes contents in skeletal muscles of two different groups of rats, one for control fed 20% casein diet, and the other experimental group recovered from 7% casein diet as protein restriction feeding for two weeks at the beginning of this experiment. Two different comparison criteria were used in this study, one for comparison between animals at the same age groups and the other between groups weighing same body weight as the control groups. Food consumption of animals for experimental and control groups were ad libitum. Following measurement and samples were collected: body weight, five different muscles-anterior tibialis (A.T.) extensor digitorium longus (E.D.L.) soleus, plantaris, gastrocnemius-for electrolytes and protein analysis. The experimental groups showed lower body weight than that of control group. Same trend was showen in protein content in five different muscles. Magnesium and potassium content in four muscles except gastrocnemius showed lower and sodium higher in experimental groups than those in control group at fourteenth day, after recovery from protein restriction, electrolytes content change showed differently in four muscles. Magnesium and potassium contents were increased as protein content in diet. Sodium content decreased as one week intake of recovery diet started, thereafter it was rather slowly increased. Phosphorus content in gastrocnemius at the second week in experimental group was slightly lower than that of control group, and it recovered rapider while at the same body weight group it was higher in experimental group.

• Korean Journal of Exercise Nutrition
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• v.13 no.1
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• pp.1-7
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• 2009

It has been shown that both caloric restriction and exercise, enhances glucose uptake through translocation of GLUT-4 protein. It remains unclear how exercise and caloric restriction affect the changes in VAMP (vesicle-associated membrane protein) in skeletal muscle and GLUT-2 in liver. This study investigated the effects of exercise training and caloric restriction on the expressions of glucose transport relating proteins in muscle and liver tissues in diabetic rats. Forty male Sprague-Dawley rats (250±10 g; 8 week in age) were assigned equally to four different groups; control (C), exercise only (E), dietary restriction only (D) and dietary restriction and exercise (DE). Daily food consumption was monitored to establish baseline intake. Both C and E groups consumed baseline food intake while D and DE groups were provided with only 60% of baseline total food intake. Forty-eight hours after intraperitoneal injection of STZ (50 mg/kg), diabetes was confirmed (8-hr fasting blood glucose levels ≥300 mg/dl). Rats in the E and DE groups exercised on a motorized treadmill for 30 min/d, 5 days/week for 4 weeks (5 min running at 3 m/min, 0% grade; 8 m/min for the next 5min, and then 15 m/min for 20 min). Rats were sacrificed 48 hrs after the last bout of exercise. Soleus muscle and liver were extracted to analyze for GLUT-4, VAMP-2, and GLUT-2, respectively. All variables were analyzed using the Western Blotting technique. All values were expressed as optical volume measured by optical density. A Two-way ANOVA was used to examine the difference between groups and applied Duncan's test for post-hoc. No significant differences in GLUT-2 expression were found among groups. However, E (280133±13228 arbitrary units{AU}) and DE (268833±14424 AU) groups showed significantly higher (p<.001) levels of GLUT-4 as compared with C (34461±2099 AU) and D groups (27847±703 AU). VAMP-2 protein expression increased (p<.001) in E (184137±7803 AU) and DE (189800±10856 AU) groups as compared to C (74201±8296AU) and D (72967±863 AU) groups. These results suggest that either exercise with or without caloric restriction increases the up-regulation of GLUT-4 and VAMP-2 in skeletal muscle of diabetic rats. However, GLUT-2 protein in liver was not affected by either exercise or exercise with caloric restriction.