• The Journal of Korean Medicine
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• v.32 no.6
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• pp.1-9
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• 2011

Objectives: We performed this study to compare the antidiabetic effects of Coptidis Rhizoma (CR) and its major component berberine with gliclazide. Materials and Methods: Diabetic rats induced by injection of streptozotocin (STZ) 55mg/kg were treated with CR 100, 200, 400mg/kg and berberine 100mg/kg. After rats were treated for 5 days, serum glucose, total cholesterol, triglyceride, BUN, creatinine and antioxidant levels were determined. Results: The cytotoxic effects of CR (0.1, 0.01, and 0.001mg/mL), berberine and gliclazide ($0.1{\mu}M$, $1{\mu}M$, and $10{\mu}M$) were tested in rat insulinoma (RIN) cells induced with 5mM STZ. The levels of fasting blood glucose, total cholesterol, triglyceride, BUN and creatinine of CR and berberine treated groups were reduced as much as that of gliclazide group in comparison to control groups, whereas total antioxidant levels increased. In vitro experiments showed that CR and berberine have a cytoprotective effect on RIN cells.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.3
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• pp.173-177
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• 2005

The purpose of this study was to discern the critical point in skeletal muscle fatty acid oxidation by changing plasma free fatty acids (FFA) level in rat. In the study, 3 key steps in lipid oxidation were examined after changing plasma FFA level by acipimox. The rates of both palmitate and palmitoylcarnitine oxidation were decreased by decrease of plasma FFA level, however, carnitine palmitoyl transferase (CPT) 1 activity was not changed, suggesting CPT1 activity may not be involved in the fatty acid oxidation at the early phase of plasma FFA change. In the fasted rats, ${\beta}-hydroxy$ acyl-CoA dehydrogenase (${\beta}$-HAD) activity was depressed to a similar extent as palmitate oxidation by a decrease of plasma FFA level. This suggested that ${\beta}-oxidation$ might be an important process to regulate fatty acid oxidation at the early period of plasma FFA change. Citrate synthase activity was not altered by the change of plasma FFA level. In conclusion, the critical step in fatty acids oxidation of skeletal muscles by the change of plasma FFA level by acipimox in fasting rats might be the ${\beta}-oxidation$ step rather than CPT1 and TCA cycle pathways.

• Journal of Environmental Health Sciences
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• v.31 no.1
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• pp.47-54
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• 2005

To evaluate the hypoglycemic effect of propolis, streptozotocin (STZ) induced diabetic rats were divided into 4 groups such as, diabetic control group, low dose of propolis (0.1 ml) group, medium dose of propolis (0.3 ml) group and high dose of propolis (0.9 ml) group and feeded with propolis extracts for 30 days. After experiment, oral glucose tolerance test (Oral GTT) was carried, and 16 hours fasting blood sugar levels, body weights, blood lipid levels were measured. Finally, pancreatic histopathological study was performed. In conclusion, the propolis is effective to the treatment diabetes due to the reduction of the blood sugar level and the regeneration of the damaged $\beta$-cells shown in streptozotocininduced diabetic rats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.6
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• pp.703-707
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• 2007

This study was performed to investigate the effect of silk protein hydrolysates hydrolyzed by protease on blood glucose level, serum insulin and leptin secretion in the OLETF rats. Twenty seven week-old-male OLETF rats were divided in three groups: diabetic control, 0.5% and 0.8% silk protein hydrolysates groups that were fed daily for 19 weeks. Body weight increased in the 0.5% and 0.8% silk protein hydrolysates fed groups compared with diabetic control group. Food and water intake were not different among diabetic and silk protein hydrolysates groups. In random state, the blood glucose levels in silk protein hydrolysates fed groups were lower than diabetic control group; however, the blood glucose in the three groups were not different in fasting state. Also silk protein hydrolysates improved the glucose tolerance in OLETF rat. The silk protein hydrolysates did not influence serum lipids while serum insulin and leptin levels were increased in the experimental OLETF rats. These results suggested that the administration of silk protein hydrolysates solution reduced significantly (p<0.05) an increasing rate of blood glucose level by stimulating the insulin secretion and increasing the serum leptin level.

• Journal of Yeungnam Medical Science
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• v.18 no.1
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• pp.94-100
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• 2001

Background: It is doubtful that aging causes deteriorated glucose metabolism and insulin resistance of skeletal muscle. Some researchers had different results about it. So we have studied the mechanism responsible for the abnormal glucose tolerance associated with aging in rapidly growing and matured rats. Materials and Methods: Animals were used S.D. rats. Growing rats were 7 weeks old (BW: 160-190 gm) and matured rats were 28 weeks old (BW: 420-525 gm). Results: Fasting blood glucose and plasma insulin levels were significantly elevated in matured rat compared with growing rats. And during oral glucose tolerance test the glucose level was also significantly elevated in matured rats. These results confirmed an insulin resistant state of aging. Insulin levels at 30 minutes of oral glucose tolerance test was significantly elevated in growing rat. But at 120 minutes it was maintained at higher level in matured rats than in growing rats. It suggested the possibility of increased insulin secretion by initial stimulation of beta-cells in growing rats, and increased secretion and decreased catabolic rate of insulin in matured rats. Glucose uptake rate of soleus muscle in matured rats was lower than that of growing rats, but the difference was not statistically significant. The dose(insulin)-responsive(glucose uptake) curve of soleus muscle was only slightly deviated to the right side. Conclusion: Glucose metabolism of rat skeletal muscle was worsened by aging. The data of glucose uptake experiments suggested the possibility of insulin resistance of skeletal muscle in matured rats. but the mechanism of insulin resistance of skeletal muscle need further studies.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.3
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• pp.334-340
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• 2012

This study was carried out to investigate the effects of Opuntia ficus-indica complex (OF) on blood glucose, glucose tolerance, plasma insulin level and histopathological appearance of pancreatic islets in streptozotoxin (STZ)-induced diabetic rats. Thirty-two male Sprague-Daweley rats were divided into non-diabetic control (NC), diabetic control (DC), diabetic OF of 2% (OF-2) and diabetic OF of 5% (OF-5) and fed experimental diets for 3 weeks. Compared to the DC group fasting blood glucose levels in the OF-2 and OF-5 groups were significantly (p<0.05) reduced while fasting plasma insulin level in the OF-2 and OF-5 groups were significantly (p<0.05) increased. Glucose tolerance in the OF-2 and OF-5 groups were improved. Histopathological observation of pancreatic islets of the OF-2 and OF-5 groups showed hyperplasia which was very similar to NC. Numbers of ${\beta}$-cells in OF-2 ($47.81{\pm}0.92$) and OF-5 ($81.64{\pm}2.80$) were higher than numbers of ${\beta}$-cells in DC ($13.18{\pm}1.01$). These results imply that the intake of OF improves ${\beta}$-cell proliferation and prevents the death of ${\beta}$-cells in STZ-induced diabetic rats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.3
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• pp.471-478
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• 2000

본 연구는 절식 및 재급여가 Sprague-Dawley 계통 수컷 흰쥐(55마리)의 지방조직내 LPL 활성과 지방합성량에 미치는 영향을 구명하였다. 아울러 재급여하는 동안 다양한 식이섭취 제한이 LPLghkf성과 지방합성에 어떻게 영향을 미치는 지도 조사하였다. 대조군(5마리)은 무제한 식이를 급여하였으며 실험 첫날 식이섭취 상태에서 바로 희생시켰으며, 그 외의 모든 쥐는 2일간 절식시켰다. 2일 절식 후 그중 5마리의 쥐를 희생하여 절식군으로 두었으며, 나머지 쥐(45마리)는 절식 후 식이를 재급여하였는데, 이때 재급여하는 동안 식이섭취 제한 효과를 보기 위해 ad libitum group, 20% food restricted group(ad libitum group의 80%) 및 40% food restricted group(ad libitum group의 60%)로 나누어 실시하였다. 재급여 후 7일, 14일 및 21일 째 되는 날 각각 희생하였다. 지방조직의 지방합성은 포도당이 총 지방으로 변한 양으로 측정하였다. 체중과 지방조직의 무게는 재급여 후 ad libitum group은 5일만에, 20% food restricted group은 14일만에 대조군 수준에 도달하였다. 재급여시 40% food restricted group의 체중과 지방조직의 무게는 재급여 후 21일째가 되도록 대조군 수준에 도달하지 못했다. 식이 재급여 후 21일 때 ad libitum group의 혈청 총 콜레스테롤함량은 대조군에 비해 높았다. (p<0.05). HDL-콜레스테롤함량은 재급여시 40% food restricted group가 대조군에 비해 높았다. (p<0.05). 그러나 HDL-C/TC비율과 중성지방함량은 처리군간에 유의적인 변화를 나타내지 않았다. 절식 후 지방조직내 지방합성량과 LPL(HR-LPL과 TE-LPL)활성은 대조군에 비해 현저희 저하되었다. (p<0.05). 재급여 후 21일째 ad libitum group의 지방합성량은 대조군에 비해 낮았다.(p<0.05). 그러나 40% food restricted group의 지방합성량은 대조군에 비해 높았다. (p<0.05). HR-LPL과 TE-LPLghkf성은 재급여시 ad libitum group과 20% food re-stricted group은 대조군 수준에 도달하였으나, 40% food restricted group은 재급여 후 21일째가 되도록 대조군 수준에 도달하지 못했다. 이러한 결과를 통해 절식 후 식이를 재급여할 경우 식이섭취 제한은 LPLghkf성이 증가되는 것을 부분적으로 혹은 완전히 예방할 수 있으며, 지방 조직내 지방축적에 영향을 미친다는 것을 말해 준다.

• The Korean Journal of Physiology
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• v.23 no.2
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• pp.401-408
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• 1989

This study was conducted to investigate whether an electrical stimulation of medial amygdaloid nucleus in rats increases pancreatic secretion. And an involvement of vagus nerve or plasma secretin in this process was also studied. In fasting rats anesthetized with urethane, a monopolar stainless steel electrode was stereotaxically inserted into the right medial amygdaloid nucleus. Pancreatic juice was collected for 20 minutes, during which physiological saline or 0.01 N HCI (0.18 ml/min) was perfused into the duodenum with or without bilateral subdiaphragmatic vagotomy. In the medial amygdaloid group, an electrical stimulation was continuously applied to the medial amygdaloid nucleus during the perfusion period. After collection of pancreatic juice, blood was drawn from the abdominal aorta for determination of the plasma secretin level. The results were as follows: 1) The electrical stimulaion of the medial amygdaloid nucleus did not influence the pancreatic secretion in response to intraduodenal saline perfusion. 2) The stimulation of the medial amygdaloid nucleus significantly increased the pancreatic secretory response (volume, bicarbonate output) to the intraduodenal 0.01 N HCI perfusion, and the increases were abolished by vagotomy. 3) The plasma secretin concentration after the intraduodenal 0.01 N HCI perfusion was higher than that after the saline perfusion. However, neither the electrical stimulation of the medial amygdaloid nucleus nor vagotomy affected the plasma secretin concentration during the intraduodenal perfusion with saline or 0.01 N HCI. It is, therefore, suggested that the medial amygdaloid nucleus facilitates the pancreatic secretion (volume, bicarbonate) elicited by intraduodenal HCI perfusion through the vagus nerve.

• Nutrition Research and Practice
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• v.3 no.2
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• pp.95-101
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• 2009

It has been reported that dietary polyunsaturated fats (PUFA) increase liver injury in response to ethanol feeding. We tested the hypothesis that diets rich in linoleic acid (18:2n-6) would affect acute liver injury after acetaminophen injection and that protein restriction might exacerbate the liver injury. We examined effects of feeding diets with either 15% (wt/wt) corn oil or 14% beef tallow and 1% corn oil for six weeks with either 6 or 20 g/100 g protein on acute hepatotoxicity. After the feeding period, liver injury was induced by injecting either with 600 mg/kg body weight acetaminophen suspended in gum arabic-based vehicle, or with vehicle alone during fasting status. Samples of liver and plasma were taken for analyses of hepatic glutathione (GSH) levels and liver-specific enzymes [(Glutamate-pyruvate transaminase (GPT) and glutamate-oxaloacetate transaminase (GOT)], respectively. Whereas GSH level was significantly lower in only group fed 15% corn oil with 6 g/100 g protein among acetaminophen-treated groups, activities of GPT and GOT were significantly elevated in all groups except the one fed beef tallow with 20 g/100 g protein, suggesting low protein might exacerbate drug-induced hepatotoxicity. The feeding regimens changed the ratio of 18:2n-6 to oleic acid (18:1n-9) in total liver lipids approximately five-fold, and produced modest changes in arachidonic acid (20:4n-6). We conclude that diets with high 18:2n-6 promote acetaminophen-induced liver injury compared to diets with more saturated fatty acids (SFA). In addition, protein restriction appeared to exacerbate the liver injury.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.3
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• pp.211-216
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• 2014

Endoplasmic reticulum (ER) stress, unfolded protein response (UPR), and mitochondrial biogenesis were assessed following varying intensities of exercise training. The animals were randomly assigned to receive either low- (LIT, n=7) or high intensity training (HIT, n=7), or were assigned to a control group (n=7). Over 5 weeks, the animals in the LIT were exercised on a treadmill with a $10^{\circ}$ incline for 60 min at a speed of 20 m/min group, and in the HIT group at a speed of 34 m/min for 5 days a week. No statistically significant differences were found in the body weight, plasma triglyceride, and total cholesterol levels across the three groups, but fasting glucose and insulin levels were significantly lower in the exercise-trained groups. Additionally, no statistically significant differences were observed in the levels of PERK phosphorylation in skeletal muscles between the three groups. However, compared to the control and LIT groups, the level of BiP was lower in the HIT group. Compared to the control group, the levels of ATF4 in skeletal muscles and CHOP were significantly lower in the HIT group. The HIT group also showed increased PGC-$1{\alpha}$ mRNA expression in comparison with the control group. Furthermore, both of the trained groups showed higher levels of mitochondrial UCP3 than the control group. In summary, we found that a 5-week high-intensity exercise training routine resulted in increased mitochondrial biogenesis and decreased ER stress and apoptotic signaling in the skeletal muscle tissue of rats.