• Food Science and Biotechnology
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• v.18 no.3
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• pp.712-716
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• 2009

The purpose of this study was to investigate the effect of dietary supplementation of sea tangle (Laminaria japonica) on the blood glucose and lipid metabolism in streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were divided into 3 groups fed control, sea tangle powder (15%, w/w), or sea tangle water extract (4%, w/w) diet. Diabetes was induced by a single injection of STZ (60 mg/kg, i.p.) in citrate buffer. The animals were fed each of the experimental diet for 13 weeks. Serum insulin was increased by dietary supplementation of sea tangle in diabetic rats. Dietary sea tangle reduced blood glucose level of diabetic rats compared to the diabetic rats fed control diet. Dietary sea tangle also reduced the serum total cholesterol, low density lipoprotein (LDL)-cholesterol, and triglyceride in the diabetic rats. While hepatic lipids were reduced, fecal excretion of lipids was increased by supplementation with dietary sea tangle in the diabetic rats. These results indicate that dietary sea tangle decreased blood glucose and improved lipid metabolism in STZ-induced diabetic rats and this effect might be exerted by increases in serum insulin and fecal excretion of lipids.

• Preventive Nutrition and Food Science
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• v.4 no.3
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• pp.200-202
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• 1999

The effectsof garlic vinegar supplementation on body weight, blood blucose, and plasma triglyceride and cholesterol were investigated in streptozotocin -induced diabetic rats fed high-cholesterol(1%) diet for 4 wk. The garlic vinegar was made by fermenting 20% frsh garlic juice. There was no effect of garlic vinegar on body weight, plasma glucose or triglyceride concentrations in the diabetic rats. Plasma total -cholesterol concentrations were unaffected by garlic vinegarr supplementation. However, plasma LDL-cholesterol concentrations and atherogenic index were significantly lower in the diabetic rats supplemented with garlic vinegar diet than tin the cotnrol rats. The diabetic-rats supplemented with garlic vinegar not only had increased HDL-cholesterol levels but had decreased LDL-cholesterol. This alteration in the HDL/LDL-cholesterol ratio in the diabetic rats may decrease the risk of atheroscelrosis. Therefore, the over-all effect of garlic vinegar supplement may contribute to the antiatherogenic role in streptozotocin-induced diabetic rats.

• Journal of Society of Preventive Korean Medicine
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• v.10 no.1
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• pp.75-93
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• 2006

Rhus verniciflua Stokes(RVS) has been widely used as a food and traditional herbal medicine in Korea. RVS has been reported that the extract from its wood and fruit has strong antioxidant activity and anticancer effect but there is little information on Lacca Sinica Exsiccata(LSE), the resin of RVS, as a medicinal use. The aim of this study was to evaluate the antidiabetic effect of ethanol-eluted extract of LSE on streptozotocin(STZ) - induced diabetic rats. Diabetes was induced in male Sprague-Dawley rats with STZ injection. Oral administration of LSE extract(50mg or 100mg/kg of body weight/day) was given to diabetic group. During 4 weeks of experiment, diabetic rats showed significant weight loss and decreasing feed efficiency ratios(FER) compared with normal rats, while the diabetic group orally fed with LSE extract showed a trend of decreasing weight loss and a significant increase of FER(p<0.05). In 4 weeks after induction of diabetes, diabetic rats showed an increase in weight of liver, kidney and heart, whereas the diabetic rats administered with LSE extract showed a reduction in the weight of heart. Blood glucose level was decreased in diabetic rats treated with LSE extract, but it was not statistically significant. Glutamic oxaloacetic transaminase, Glutamic pyruvate transaminase and total cholesterol levels were lower in the diabetic group treated with LSE extract than in untreated diabetic group, but not significant. These results present that LSE may partly have antidiabetic effect and may protect against the development of diabetic heart complications resulting from impaired glucose metabolism.

• Journal of Nutrition and Health
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• v.32 no.3
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• pp.230-238
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• 1999

The present study was conducted to investigate te effect of sea tangle and hypoglycemic agent(Metformin) on lipid peroxidation and antioxidants levels in normal and diabetic rats. Male Sprague-Dawley rats were fed AIN-76 based experimental diets containing 5% (w/w) cellulose or 15%(w/w) sea tangle for 3 weeks, and then rats of diabetic groups were rendered diabetic by intramuscular injection of streptozotocin(STZ, 45mg/kg BW). After induction of diabetes Metformin(350mg/kg BW) was given once a day using a feeding tube for 5 days. Blood glucose level in diabetic rats fed sea tangle was significantly lower than that of diabetic rats fed cellulose. Metformin feeding resulted in further lowering blood glucose. Plasma and liver microsomal levels of lipid peroxides were increased significantly in diabetic rats as compared to normal rats, and the plasma level tended to be decreased by sea tangle feeding. Plasma level of retinol was reduced by STZ treatment, but it was increased by Metformin feeding in diabetic rats fed sea tangle. The liver contents of retinyl plamitate were reduced in diabetic rats but recovered by sea tangle feeding to some extent. Liver contents of total vitamin A were increased significantly by sea tangle in diabetic rats. Although difference in either plasma or liver level of $\alpha$-tocopherol by diet and STZ treatment was not significant, $\alpha$-tocopherol levels were the highest in the group with simultaneous feeding of sea tangle and metformin. Liver contents of zinc and copper were not influenced by either STZ treatment or sea tangle feeding. The present study indicates that the lowering blood glucose level could be attained by simultaneous trial of sea tangle diet and hypoglycemic agent and the increased oxidative stress caused by STZz treatment could be relieved by sea tangle feeding.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.2
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• pp.321-327
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• 2008

This study evaluated neuroprotective effects of Yanggyuksanhwa-tang (YST) on global cerebral ischemia of diabetic rats. On primary experiment, diabetic condition in rats was induced by streptozotocin injection. Secondarily, global cerebral ischemia was induced by bilateral occlusion of the common carotid artery with hypotension (BCAO) under the diabetic condition. Then neuroprotective effect of YST was observed with changes of neuronal c-Fos and Bax expressions, and GFAP expression in the brain tissues by using immunohistochemistry. YST treatment was resulted significant decrease of c-Fos expression in CA1 hippocampus induced by BCAO on diabetic rats. YST treatment was resulted significant decrease of Bax expression in CA1 hippocampus induced by BCAO on diabetic rats. YST treatment was resulted significant decrease of c-Fos expression in cerebral cortex and caudoputamen induced by BCAO on diabetic rats. YST treatment was resulted significant decrease of GFAP expression in cerebral cortex induced by BCAO on diabetic rats. These results suggest that YST has effects on neuroprotection against cerebral ischemic damage under diabetic condition. And it is supposed that neuroprotective effect of YST reveals by anti-apoptosis mechanism.

• The Korean Journal of Physiology
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• v.30 no.2
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• pp.231-236
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• 1996

In our previous study (Kim et al, 1991), GLUT 4 protein content correlated negatively with plasma glucose levels in skeletal muscles of STZ-induced diabetic rats. Thus, in this study, to confirm whether expression of GLUT 4 correlate negatively with degree of hyperglycemia, we measured levels of GLUT 4 mRNA in red and white gastrocnemius muscles in STZ-induced mild and severe diabetic rats. Rats were randomly assigned to control, mild, and severe diabetic groups, and the diabetes was induced by intraperitoneal administration of STZ. The experiment was carried out 10 days after STZ administration. Gastrocnemius red and white muscles were used fur the measurement of GLUT 4 expression. Plasma glucose levels of mild and severe diabetic rats were increased compared to control rats (control, mild, and severe diabetes; $6.4{\pm}0.32,\;9.4{\pm}0.68,\;and\;22.0{\pm}0.58$ mmol/L, respectively). Plasma insulin levels of mild and severe diabetic rats were decreased compared to control rats (control, mild, and severe diabetes; $198{\pm}37,\;l14{\pm}14,\;and\;90{\pm}15$ pmol/L, respectively). GLUT 4 mRNA levels of gastrocnemius red muscles in mild and severe diabetic rats were decreased compared to control rats ($64{\pm}1.2%\;and\;71{\pm}2.0%$ of control, respectively), but GLUT 4 mRNA levels in gastrocnemius white muscles were unaltered in diabetic rats. In summary, GLUT 4 mRNA levels were decreased in STZ-induced diabetic rats but did not correlated negatively with degree of hyperglycemia, and this result suggest that the regulatory mechanisms of decreased GLUT 4 mRNA levels are hypoinsulinemia and/or other metabolic factor but not hyperglycemia. And regulation of GLUT 4 expression in STZ-induced diabetes between red and white enriched skeletal muscles may be related to a fiber specific gene regulatory mechanism.

• Journal of Nutrition and Health
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• v.36 no.7
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• pp.675-683
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• 2003

This study investigated the effect of dietary $\beta$-carotene supplementation on lipid peroxidation and anti oxidative enzyme activity as indices of oxidative stress in diabetic rats. Fifty Sprague-Dawley male rats aging 7 weeks were used as experimental animals, which were divided into the non-diabetic control group and the diabetic group. The diabetic group received an intraperitoneal injection with streptozotocin to induce diabetes. Then the diabetic rats were divided into four dietary groups which contained different amounts of $\beta$-carotene; 0%, 0.002%, 0.02%, or 0.2% of the diet. The diabetic rats were fed the experimental diets and the non-diabetic rats were fed the basal diet without $\beta$-carotene supplementation for 2 weeks and then sacrificed. The diabetic group had a significantly higher blood glucose level than the non-diabetic group. However, blood glucose level were not significantly changed by the level of dietary $\beta$-carotene supplementation. Compared to the non-diabetic control group, the diabetic control group indicated a significant increase of plasma thiobarbituric acid reactive substance (TBARS). Liver TBARS level also tended to be higher in diabetic control group, although it was not significant. The $\beta$-carotene supplementation did not reduce plasma TBARS level. However, Liver TBARS level was significantly decreased when 0.02% or more $\beta$-carotene was supplemented in the diet. The liver lipofuscin level in the diabetic control group was higher than in the non-diabetic control group, but the effect of $\beta$-carotene supplementation did not show any differences. Superoxide dismutase activity was significantly lower in the diabetic group, but it was increased in groups receiving 0.02% or more $\beta$-carotene. Compared to the non-diabetic control group, lower activities of catalase and glutathione peroxidase were observed in the diabetic control group, although it was not significant. Catalase and glutathione peroxidase activities tended to increase as the levels of $\beta$-carotene supplementation increased, although it was not statistically significant. Therefore, it seems that dietary $\beta$-carotene supplementation might reduce diabetic complications by partly decreasing the lipid peroxidation and increasing the activity of antioxidative enzyme in diabetes.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.4
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• pp.375-382
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• 1999

Growing evidence indicates that enhanced generation or actions of nitric oxide (NO) are implicated in the pathogenesis of hypertension in spontaneously hypertensive rats and diabetic nephropathy in streptozotocin (STZ)-induced diabetic rats. We investigated whether inducible nitric oxide synthase (iNOS) expression in STZ-induced diabetic rats is responsible for the alterations of vascular reactivity. Diabetic state was confirmed 28 days after injection of STZ (i.p) in rats by measuring blood glucose. In order to evaluate whether short term (4 weeks) diabetic state is related with altered vascular reactivity caused by iNOS expression, isometric tension experiments were performed. In addition, plasma nitrite/nitrate (NOx) levels and expression of iNOS in the lung and aorta of control and STZ-treated rats were compared by using Griess reagent and Western analysis, respectively. Results indicated that STZ-treated rats increased the maximal contractile response of the aorta to phenylephrine (PE), and high $K^+,$ while the sensitivity remained unaltered. Endothelium-dependent relaxation, but not SNP-mediated relaxation, was reduced in STZ-treated rats. Plasma nitrite/nitrates are significantly increased in STZ-treated rats compared to controls. The malondialdehyde (MDA) contents of liver, serum, and aorta of diabetic rats were also significantly increased. Furthermore, nitrotyrosine, a specific foot print of peroxynitrite, was significantly increased in endothelial cells and smooth muscle layers in STZ-induced diabetic aorta. Taken together, the present findings indicate that enhanced release of NO by iNOS along with increased lipid peroxidation in diabetic conditions may be responsible, at least in part, for the augmented contractility, possibly through the modification of endothelial integrity or ecNOS activity of endothelium in STZ-diabetic rat aorta.

• Environmental Analysis Health and Toxicology
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• v.21 no.2 s.53
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• pp.139-146
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• 2006

The purpose of this study was to investigate the effects of dietary chungguajang powder on blood glucose level and hepatic activities of antioxidant enzymes in normal and streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley male ratt ($200{\sim}220g$) of six groups including normal group fed normal diet (N), diabetic group fed normal diet (C), diabetic groups fed chunggugjang powder diet (DC-1%, DC-5%, DC-10%, DC-20%) were used for the experiments. Diabetes was induced by single intraperitoneal injection of streptozotocin as a dose of 70 mg/kg body weight. After 3 weeks the animals were sacrificed and hepatic activities of antioxidant enzymes, serum level of glucose and organ weight were evaluated. Food and water intakes were higher in diabetic groups than normal group. Body weight gain and food efficiency ratio were lower in diabetic groups. However, they were higher in chunggugjang diet groups (DC) than normal diet group (C). The serum glucose levels were significantly lower (p<0.05) in the diabetic groups fed chunggugjang diet (DC-10%, DC-20%) than diabetic group fed normal diet (C). Hepatic activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione S-transferase were lower in diabetic groups than normal group and they were significantly lower in diabetic groups fed chunggugjang diet (DC-20%) compared to diabetic rats fed normal diet (p<0.05). In conclusion, these results indicated that chunggugjang powder would have antidiabetic and antioxidant effects in STZ-induced diabetic rats.

• Journal of the Korean Society of Food Culture
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• v.22 no.1
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• pp.140-148
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• 2007

Diabetic nephropathy has been increasing, although blood glucose and blood pressure can be controlled by angiotensin converting enzyme(ACE) or advanced glycosylation end products(AGE) inhibitors in the diabetic patients. We investigated the effect of dietary supplementation of sea tangle on the blood glucose, and pathological scoring of diabetic kidneys in the streptozotocin(STZ) induced diabetic rats. Male Sprague-Dawley rats were divided into normal rats fed control diet and diabetic rats fed control diet or control diet supplemented with powder or oater extract of sea tangle. Diabetes was induced by a single injection of STZ(60mg/kg, ip) in citrate buffer. The animals were fed the experimental diet and water for 13 weeks. Dietary supplementation of sea tangle decreased blood glucose in the diabetic rats. However, dietary supplementation of sea tangle did not affect the antioxidant enzyme activities, MDA content and pathology of diabetic kidneys. These results indicate that decreased blood glucose by sea tangle could not delay the progression of diabetic kidney disease.