• Preventive Nutrition and Food Science
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• v.21 no.3
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• pp.181-186
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• 2016

This study was designed to investigate the inhibitory effect of Gynura procumbens extract against carbohydrate digesting enzymes and its ability to ameliorate postprandial hyperglycemia in streptozotocin (STZ)-induced diabetic mice. G. procumbens extract showed prominent ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibitory effects. The half-maximal inhibitory concentration ($IC_{50}$) of G. procumbens extract against ${\alpha}$-glucosidase and ${\alpha}$-amylase was $0.092{\pm}0.018$ and $0.084{\pm}0.027mg/mL$, respectively, suggesting that the ${\alpha}$-amylase inhibition activity of the G. procumbens extract was more effective than that of the positive control, acarbose ($IC_{50}=0.164mg/mL$). The increase in postprandial blood glucose levels was more significantly alleviated in the G. procumbens extract group than in the control group of STZ-induced diabetic mice. Moreover, the area under the curve significantly decreased with G. procumbens extract administration in STZ-induced diabetic mice. These results suggest that G. procumbens extract may help alleviate postprandial hyperglycemia by inhibiting carbohydrate digesting enzymes.

• Preventive Nutrition and Food Science
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• v.19 no.1
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• pp.5-9
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• 2014

This study was designed to investigate the inhibitory effects of Polyopes lancifolia extract (PLE) on ${\alpha}$-glucosidase activity, ${\alpha}$-amylase activitiy, and postprandial hyperglycemia in streptozotocin (STZ)-induced diabetic mice. The results of this study revealed a marked inhibitory effect of PLE on ${\alpha}$-glucosidase and ${\alpha}$-amylase activities. The $IC_{50}s$ of PLE against ${\alpha}$-glucosidase and ${\alpha}$-amylase were 0.20 mg/mL and 0.35 mg/mL, respectively. PLE was a more effective inhibitor of ${\alpha}$-glucosidase and ${\alpha}$-amylase activities than acarbose, the positive control. The postprandial blood glucose levels of STZ-induced diabetic mice were significantly lower in the PLE treated group than in the control group. Moreover, PLE administration was associated with a decreased area under the curve for the glucose response in diabetic mice. These results indicate that PLE may be a potent inhibitor of ${\alpha}$-glucosidase and ${\alpha}$-amylase activities and may suppress postprandial hyperglycemia.

• Molecules and Cells
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• v.40 no.7
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• pp.457-465
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• 2017

Streptozotocin (STZ)-induced murine models of type 1 diabetes have been used to examine ER stress during pancreatic ${\beta}$-cell apoptosis, as this ER stress plays important roles in the pathogenesis and development of the disease. However, the mechanisms linking type 1 diabetes to the ER stress-modulating anti-diabetic signaling pathway remain to be addressed, though it was recently established that ERK5 (Extracellular-signal-regulated kinase 5) contributes to the pathogeneses of diabetic complications. This study was undertaken to explore the mechanism whereby ERK5 inhibition instigates pancreatic ${\beta}$-cell apoptosis via an ER stress-dependent signaling pathway. STZ-induced diabetic WT and CHOP deficient mice were i.p. injected every 2 days for 6 days under BIX02189 (a specific ERK5 inhibitor) treatment in order to evaluate the role of ERK5. Hyperglycemia was exacerbated by co-treating C57BL/6J mice with STZ and BIX02189 as compared with mice administered with STZ alone. In addition, immunoblotting data revealed that ERK5 inhibition activated the unfolded protein response pathway accompanying apoptotic events, such as, PARP-1 and caspase-3 cleavage. Interestingly, ERK5 inhibition-induced exacerbation of pancreatic ${\beta}$-cell apoptosis was inhibited in CHOP deficient mice. Moreover, transduction of adenovirus encoding an active mutant form of $MEK5{\alpha}$, an upstream kinase of ERK5, inhibited STZ-induced unfolded protein responses and ${\beta}$-cell apoptosis. These results suggest that ERK5 protects against STZ-induced pancreatic ${\beta}$-cell apoptosis and hyperglycemia by interrupting the ER stress-mediated apoptotic pathway.

• The Korean Journal of Pharmacology
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• v.24 no.1
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• pp.125-134
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• 1988

A single i.v. dose of streptozotocin (65 mg/kg) given to rats has produced a marked hyper-glycemia (>500 mg serum glucose/dl). Since the Atractylodis Rhizoma is known to have hypo-glycemic action, the water extracts of Atractylodis Rhizoma (ARWE) was given to the streptozotocin-induced (SZ) hyperglycemic rats. To determine whether ARWE has the anti-hyperglycemic effects, two different daily doses of ARWE (i.e.0.2 g/kg and 2.0 g/kg) were given orally to the SZ rats for up to 8 days. Thereupon, serum levels of glucose, insulin, amylase and cholesterol were determined on days 1, 3 and 8, following the initial and repeated daily administrations of ARWE. On day 8, glycogen content and glucose-6-phosphatase activity in the liver were assayed. Results showed that ARWE decreased the serum glucose levels, which had been markedly elevated by the SZ pre-treatment. In support of this, the serum insulin level, which had been quickly lowered by the SZ pre-treatment $(20{\mu}U/ml)$, was quickly elevated in the ARWE dose dependent manner that, at 2.0 g/kg ARWE, the serum insulin level was increased $(20{\mu}U/ml)$ above the normal level $(42{\mu}U/ml)$. Also, the serum amylase level, which was steadily decreasing after the SZ pre-treatment, was restored to the normal level folowing 8 day of ARWE (2.0 g/kg) treatment. Hepatic glycogen content and glucose-6-phosphatase activity, which decreased and increased, respectively in the 52 treatment group, were restored toward the normal level in SZ plus ARWE group.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.6
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• pp.818-824
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• 2011

Eight LW${\times}$D crossbred, castrated weanling piglets were used to examine the effect of hyperglycemia by streptozotocin (STZ)-injection on oxidative and anti-oxidative status in circulating fluid. Every two of the eight piglets were intravenously administrated STZ at a dose of 0 (control), 100, 125 or 150 mg/kg BW, respectively, and on 15th day after the STZ-injection, some markers of the oxidative stress in circulating fluid were measured to evaluate oxidative and anti-oxidative status in the piglets. First, piglets with hyperglycemia were selected from the STZ-injected piglets as measured by the levels of fasting plasma glucose (FPG) during 2 weeks after the STZ-injection. Additionally, data obtained from the intravenous glucose tolerance test (IVGTT) on 14th day were analyzed. Secondly, the data obtained in this experiment were divided into the control group and the hyperglycemic (STZ) group, and compared. The FPG level or area under curve (AUC) for plasma glucose during the IVGTT in the STZ-induced diabetic piglets was slightly significantly (FPG, p = 0.070; AUC, p = 0.072) higher compared with the control. On the other hand, the plasma level of lipid peroxidation in the STZ-induced diabetic piglets was significantly (p<0.05) higher compared with the control. These results raise the possibility that STZ-induced diabetic piglets produced in this study can be used as a diabetic animal model to research the pathogenic mechanisms or therapy of complications in diabetic mellitus.

• Korean Journal of Pharmacognosy
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• v.23 no.2
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• pp.96-105
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• 1992

The studies were attempted to evaluated the therapeutic effects of various fractions(ether, methanol, butanol) of Caragana chamlagu roots on the hyperlipemia induced by feeding the diet containing 1%, cholesterol and 0.5%, cholic acid in rats, and on the hyperglycemia induced by streptozotocin in rats. Also the preventive effects of these fractions were studies on the liver damage in $CCl_4-intoxicated$ rats. The followings were obtained as the results: 1.The butanol fraction was significantly shown to down the serum lipid level in 1%, cholesterol and 0.5%, cholic acid diet-feeding rats and streptozotocin-induced hyperglycemic rats. Cholesterol level in $CCl_4-intoxicated$ rats was reduced in the case of all pre-treated groups. 2.The serum glucose level of streptozotocin-induced hyperglycemic rats was significantly decreased by the administration of various fractions of C. chamlagu roots, and the lipid-peroxidation of pancreas was significantly decreased in the case of administration of these fractions. 3.The activates of s-GOT and s-GPT were decreased by the administration of various fractions, especially in butanol fraction, of C. chamlagu roots in the $CCl_4-intoxicated$ rats. The liver lipid-peroxidation was decreased by administration of 200mg/kg of these fractions in the $CCl_4-intoxicated$ rats. In histological observation, hepatic cellular necrosis and fatty acid deposit were increased remarkably by $CCl_4-intoxication$, but the pretreatment of various fractions of C. chamlagu roots improved the pathological change of parenchymatous cell necrosis and fatty change around centrilobular area of the control.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.3
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• pp.742-745
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• 2003

This study was carried out to investigate the optimal mixed extract with Acanthopanax Chiisanensis Nakai in order to strengthen anti-diabetic effects on the hyperglycemia induced by streptozotocin in mice. The original Bambusae Caulis in Liquamen filtered and refined. The effects of Acanthopanax Chiisanensis Nakai with Bambusae Caulis in Liquamen were administered to mice for 4weeks and its anti-diabetic effect examined. Mice used in this experiment were divided into two groups and distrilled water(control), Acanthopanax Chiisanensis Nakai mixed with refined Bambusae Caulis in Liquamen(AC+BCL.D) were given orally for 28days respectively. And then, experimental groups were observed in terms of blood sugar, creatinine, BUN and GPT. The amount of glucose was significantly decreased compared with the control group(P < 0.01). The amount of creatinine was decreased compared with the control group(P < 0.05). The amount of GPT did not show any differences between two groups.

• YAKHAK HOEJI
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• v.36 no.1
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• pp.80-86
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• 1992

Streptozotocin (STZ) is a naturally occurring nitrosoamide used extensively to produce diabetes in experimental animals. Our previous study has demonstrated that i.v. administraton of streptozotocin induces significant red blood cell hemolmysis in rats. Since it has been reported that the highest concentration of STZ is found in the liver, the effect of STZ in freshly isolated rat hepatocytes has been investigated. STZ treatment (10 mM) did not cause significant loss of viability throughout 4 hour incubation, while high dose of STZ (300 mM) to hepatocytes resulted in complete cell death within 3 hours. Addition of 40 mM glucose to incubation medium did not potentiate STZ-induced hepatotoxicity, suggesting that STZ-induced hyperglycemia in vivo did not affect its hepatotoxicity. To investigate the mechanixm of the toxicity, intracellular total glutathione level was determined. Tratment with 10 mM STZ which was not toxic to hepatocytes led to complete depletion of intracellular glutathione level within 1 hour incubation. These results suggest that STZ-induced hepatotoxicity may be independent on the intracellular glutathione depletion.

• Journal of Life Science
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• v.8 no.4
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• pp.381-386
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• 1998

This study was designed to observe the effects of the feeding Gentiana scabra Bunge var.buergeri Max. extract on the improvement of the blood glucose, lipids in the serum of streptozotcin(55mg/kg of body weight, I.P. injection) induced hyperglycemic rats (S.D. strain, ) fed the experimental diets for 4 weeks. Concentrations of blood glucose were significantly higher in the streptozotocin administration(I.P.) groups (group 2(streptozotcin+water), 3(streptozocin+Gentiana scabra Bunge extract), 4(streptozotocin+cholesterol+water), 5(streptozotocin+cholesterol+Gentiana scabra Bunge extract) than those in the control group(group 1(water)). Bolld glucose concentrations were rather lower in the group 3(streptozotocin+Gentiana scabra Bunge extract)than in the group 2(streptozotocin+water), and then those of the group 5 were rather lower than in the group 4. There was almost little significance among the groups. concentrations of total cholesterol in serum were lower in the group 5 than those in the group 4, and the group 3 were rather lower than in the group 2. Concentrations of LDL-cholesterol in serum were significantly lower in the group 3 than those 2. In the ratio of HDL-cholesterol concentrations to total cholesterol concentrations, Gentiana scabra Bunge extract administration groups were higher percentage than the other goups. Concentrations of free cholesterol and cholesteryl ester in serum were rather lower in the groups 3,5 than the other groups, and then those of the group were higher percentage than the other groups. concentrations of free cholesterol and cholesteryl ester in serum were rather lower in the groups 3,5 than the groups, and then those of the group 3 were significantly lower than in the group 4. Concentrations of triglyceride and phospholipid in serum were decreased in the group 3 than in the other groups. The activities of aspartate aminotransferase and alanine aminotransferase in serum were increased in the all experimental groups than in the control group. From the above research, the Gentiana scabra Bunge var.buergeri Max. extracts were effective on the improvement of the lipid compositions in serum of streptozotcin induced hyperglycemic and hypercholosterolemic rats.

• Journal of Life Science
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• v.14 no.2
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• pp.245-251
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• 2004

Exercise is beneficial to the diabetic patients and streptozotocin-induced diabetic rat has been used for the study of exercise effect. The purpose of this study was to establish the optimal condition of induction of hyperglycemic diabetic rat using streptozotocin and to examine the preventive effect of treadmill exercise on the diabetic rat before and after streptozotocin injection. Intraperitoneal injection of increasing amount of streptozotocin up to 40 mg/kg dose-responsively induce hyperglycemic diabetic rat and inversely reduced the blood insulin level. Body weight was also gradually reduced with the increasing amount of streptozotocin. Control and diabetic rats exercised for 4 weeks before streptozotocin injection. The exercise was performed in the treadmill for 25 minutes a day and 5 times a week with low intensity (0 degree tilt, 15 m/min velocity). Following streptozotocin injection, the blood glucose level was measured every week and the rat was sacrificed after 4 weeks to measure the concentration of insulin and blood lipids. The blood levels of glucose and insulin was significantly reduced with exercise before streptozotocin injection, while those were not changed after streptozotocin injection. The levels of blood lipids such as total cholesterol, HDL-cholesterol, LDL-cholesterol and triglyceride were close to normal control rats. From this study, researchers found the optimal condition of preparation of streptozotocin-induced hyperglycemic diabetic rat, and the mild treadmill exercise has beneficial effect on preventing hyperglycemia and hyperlipidemia. Thus, even low intensive running prevent not only diabetes but also diabetic vascular complications.