• Preventive Nutrition and Food Science
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• v.2 no.2
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• pp.144-148
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• 1997

Insulin secretory response to various calcium concentrations was investigated in 10- to 12-week old male lean and obese Zucker rats using an in vitro pancreatic perfusion procedure. There was no significant difference in insulin secretion response to low, medium, and high calcium concentrations in the lean rat. However, the obese rat shows a characteristics of hypersecretion of insulin. The obese rat pancreas perfused with the low calcium concentration released as low insulin as the lean rat. When perfused with the medium calcium concentration, th obese rat pancreas released twice as much insulin as the lean rat. eh hypersecretory phenomenon was also seen in the obese rat pancreas perfused with the high calcium concentration during the first phase of erfusion period, but his phenomenon was gradually diminished during he second phase of perfusion period. These results indicate that there may be a selective insulin secretory response to the extracellular calcium in he obese Zucker rat pancreas.

• YAKHAK HOEJI
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• v.37 no.4
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• pp.341-349
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• 1993

To determine the reason of individual variation of the effect of caffeine, the absorption and the disposition of caffeine were studied in caffeine sensitive and caffeine nonsensitive volunteers. And also to study the effect of obesity on caffeine pharmacokinetics, the caffeine disposition in the obese rat and in the lean rat were investigated respectively. In result the caffeine sensitive group showed a longer terminal half-life of caffeine(7.35$\pm$0.71 hr : 5.49$\pm$0.73 hr) and a larger AUC (55.42$\pm$9.09 $\mu\textrm{g}$.$ml^{-1}$.hr:44.0$\pm$7.81$\mu\textrm{g}$.$ml^{-1}$.hr) than that of caffeine non-sensitive group without statistical significance. The obese rat showed a longer terminal half-life (3.47 hr : 2.31 hr) and a larger AUC(35.3 $\mu\textrm{g}$.$ml^{-1}$.hr:26.97$\mu\textrm{g}$.$ml^{-1}$.hr) than that of the lean rat. But there was no correlation in the amount of daily caffeine consumption and obesity. In conclusion, we suggest that the individual variation of the effect of caffeine are being caused from the individual differences of caffeine susceptibility or tolerance rather than the differences of the genetic metabolic capacity or metabolic tolerance.

• Journal of Nutrition and Health
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• v.23 no.6
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• pp.451-458
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• 1990

Lean and obese male spontaneously hypertensive(SHR/Mcc-cp) rats were fed a ground rat chow diet with or without 0.001% estrone added from 6 to 18 weeks of age. Urine samples were collected weekly with 24 hour fasting. Both control lean and obese rats showed significantly higher urinary protein than their estrone treated counterparts. Treatment with 0.001% estrone diet was found to reduced the proteinuria in the maturing lean and obese SHR/Mcc-cp rats. Peaks in urinary protein level were noted at 16 weeks of age in both lean and obese control rats. Both control and estrone treated lean rats showed higher proteinuria than the obese rats. Therefore, obesity does not appear to be a contributing factor to the proteinuria in young male SHR/Mcc-cp rats.

• Toxicological Research
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• v.34 no.1
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• pp.41-48
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• 2018

The efficacy of highly active antiretroviral therapy (HAART) has led to an increase demand for therapeutic use, thereby necessitating investigation into drug toxicity. This study was designed to investigate the in vivo effects of HAART on sperm parameters and testicular oxidative stress in lean and obese rats. Wistar rats (males, n = 40, weighing 180~200 g) were assigned randomly into 4 groups and treated accordingly for 16 weeks as follows: Control (C): lean group fed with standard rat chow; Diet induced obesity (DIO): obese animals fed a high caloric diet; C + ART: lean animals treated with HAART; DIO + ART: obese animals treated with HAART. An antiretroviral drug combination of Tenofovir, Emtricitabine and Efavirenz at a dose of 17, 26 and 50 mg/kg/day was administered for the latter 6 weeks via jelly cube feeding. At the end of the experimental period, sperm analysis was performed on sperm collected from the caudal epididymis, while the testis was homogenized for antioxidant enzyme and lipid peroxidation assays. Results showed that HAART significantly decreased sperm motility (p < 0.05) in both lean and obese animals, and viability (p < 0.05) in the DIO group. Testicular glutathione, catalase and superoxide dismutase were significantly decreased (p < 0.05), while Thiobarbituric acid reactive substances (TBARS) levels were significantly increased (p < 0.05) when the DIO+ART group was compared to Control group. Thus, the decreased sperm qualities associated with HAART might be as a result of increased testicular oxidative stress prominent in obese animals.

• Preventive Nutrition and Food Science
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• v.22 no.3
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• pp.172-183
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• 2017

Vitamin A and its metabolites modulate insulin resistance and regulate stearoyl-CoA desaturase 1 (SCD1), which are also known to affect insulin resistance. Here, we tested, whether vitamin A-mediated changes in insulin resistance markers are associated with SCD1 regulation or not. For this purpose, 30-week old male lean and glucose-intolerant obese rats of WNIN/GR-Ob strain were given either a stock or vitamin A-enriched diet, i.e. 2.6 mg or 129 mg vitamin A/kg diet, for 14 weeks. Compared to the stock diet, vitamin A-enriched diet feeding improved hyperglycemia and glucose-clearance rate in obese rats and no such changes were seen in lean rats receiving identical diets. These changes were corroborated with concomitant increase in circulatory insulin and glycogen levels of liver and muscle (whose insulin signaling pathway genes were up-regulated) in obese rats. Further, the observed increase in muscle glycogen content in these obese rats could be explained by increased levels of the active form of glycogen synthase, the key regulator of glycogen synthesis pathway, possibly inactivated through increased phosphorylation of its upstream inhibitor, glycogen synthase kinase. However, the unaltered hepatic SCD1 protein expression (despite decreased mRNA level) and increased muscle-SCD1 expression (both at gene and protein levels) suggest that vitamin A-mediated changes on glucose metabolism are not associated with SCD1 regulation. Chronic consumption of vitamin A-enriched diet improved hyperglycemia and glucose-intolerance, possibly, through the regulation of intracellular signaling and glycogen synthesis pathways of muscle and liver, but not associated with SCD1.

• Journal of Nutrition and Health
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• v.39 no.4
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• pp.323-330
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• 2006

Peripheral insulin resistance in obese/type II diabetes animals results from an impairment of insulin-stimulated glucose uptake into skeletal muscle. Insulin stimulate the translocation of GLUT4 from intracellular location to the plasma membrane. Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) is implicated in mediation of fusion of GLUT4-containing vesicle with the plasma membrane. Present study investigated regulatory effects of Rhodiola sachalinensis administration and exercise training on the expression of GLUT4 protein and SNAREs protein in skeletal muscles of obese Zucker rats. Experimental animals were randomly assigned into one of five groups ; lean control(LN), obese control(OB), exercise-treated(EXE), Rhodiola sachalinensis-treated(Rho), combine of Rho & EXE (Rho-EXE). All animals of exercise training (EXE, Rho-EXE) performed treadmill running for 8 weeks, and animals of Rho groups (Rho, Rho-EXE) were dosed daily by gastric gavage during the same period. After experiment, blood were taken for analyses of glucose, insulin, and lipids levels. Mitochondrial oxidative enzyme (citrate synthase, CS ; $\beta$-hydroxyacyl-CoA dehydrogenase, $\beta$-HAD) activity were analysed. Skeletal muscles were dissected out for analyses of proteins (GLUT4, VAMP2, syntaxin4, SNAP23). Results are as follows. Exercise and/or Rhodiola sachalinensis administration significantly reduced body weight and improved blood lipids (TG, FFA), and increased insulin sensitivity. Endurance exercise significantly increased the activity of mitochondrial enzymes and the expression of GLUT4 protein, however, administration of Rhodiola sachalinensis did not affect them. The effect of exercise and/or Rhodiola sachalinensis administration on the expression of SNARE proteins was unclear. Our study suggested that improvement insulin sensitivity by exercise and/or Rhodiola sachalinensis administration in obese Zucker rats is independent of expression of SNARE proteins.

• The Journal of Korean Medicine
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• v.25 no.4
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• pp.200-208
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• 2004

Objective: Non-insulin Dependent Diabetes Mellitus (NIDDM) is characterized by insulin resistance, which affects the glucose transportation inside the cell. The purpose of this study was to find out how Palmijihwangtang (PMT) and exercise influence the glucose transport metabolism in the organ muscles of ZDF (zucker diabetic fatty) rat with insulin resistance. Methods: Using three male normal zucker rats and twelve male obese rats, they were divided into a normal lean group (N=3), obese control group (N=3), obese exercises group (N=3), obese medication group (N=3), obese exercise and medication group (N=3). Treadmill exercise were repeated with 27m/min speed for an hour a day, five days a week, for 8 weeks. And 20β/sub ￠/ of PMT was orally administered twice a day for 8 weeks, after that a period blood sample was exsanguinated by heart perforation and was analyzed. Results: The body weight of the OM and OEM group showed a significant decrease among all the obese groups. The blood insulin level increased significantly of all groups in comparison with the N group. All of the OE, OM and the OEM groups showed a significant decrease of insulin level compared with the OC group; especially the OEM group demonstrated the most among obese groups. Regarding GLUT-4 level, OEM was the unique group showed a significant increase among all the obese groups. The VAMP-2 level in myocardium cell membrane was increased significantly at OC group in comparison with the N group, whereas the OEM group only showed significant decrease of it. In addition, the VAMP-2 level in pancreas β-cell was significantly decreased at all the obese groups in comparison with the N group. Only the OEM group showed significant increase among all the obese groups. Conclusion: Palmijihwangtang (PMT) and exercise could effectively promote the insulin metabolism in pancreas β-cells and activate the glucose transport process in myocardium cell membrane by lowering the insulin resistance of ZDF rats.