Hypolactatemic effect of sodium difluoroacetate

In the anesthetized rat, the intraperitoneal injection of 40 mg/kg sodium difluoroacetate (DFA), an activator of the pyruvate dehydrogenase, counteracted the hyperlactatemia induced by a high dose of phenformin (40 mg/kg) injected concomitantly. In the normal conscious dog, the administration of 150 mg/kg by gastric intubation decreased the blood lactate and pyruvate levels; however, this effect was less marked than that produced by the same dose of sodium dichloroacetate (DCA).     

Effect of sodium molybdate on carbohydrate metabolizing enzymes in alloxan-induced diabetic rats

We evaluated the effect of sodium molybdate on carbohydrate metabolizing enzymes and mitochondrial enzymes in diabetic rats. Diabetic rats showed a significant reduction in the activities of glucose metabolising enzymes like hexokinase, glucose-6-phosphate dehydrogenase, glycogen synthase and in the level of glycogen. An elevation in the activities of aldolase, glucose-6-phosphatase, fructose 1,6- bisphosphatase, glycogen phosphorylase and in the level of blood glucose were also observed in diabetic rats when compared to control rats. The activities of mitochondrial enzymes isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, NADH-dehydrogenase and cytochrome-C-oxidase were also significantly lowered in diabetic rats. Molybdate administration to diabetic rats reversed the above changes in a significant manner. From our observations, we conclude that administration of sodium molybdate regulated the blood sugar levels in alloxan-induced diabetic rats. Sodium molybdate therapy not only maintained the blood glucose homeostasis but also altered the activities of carbohydrate metabolising enzymes. Molybdate therapy also considerably improved the activities of mitochondrial enzymes, thereby suggesting its role in mitochondrial energy production.     

Effect of restraint stress on prolactin and corticosterone levels in streptozotocin-induced diabetic rats

Changes in neuroendocrine function have been shown to occur in diabetic animals. The aim of the present study was to examine both the prolactin (PRL) and corticosterone (CORT) responses to a short period of restraint stress after the animals had been made diabetic for six weeks. The streptozotocin - induced diabetic rats had resting CORT levels which were significantly higher than the control animals. Acute restraint significantly increased CORT levels in both the control and diabetic rats. The CORT levels after stress were higher in the diabetic rats. However, the magnitude of the response (percent increase) was less in these animals. The resting PRL levels were not significantly different in the diabetic and control animals. The PRL levels significantly increased in both the control and diabetic rats when they were exposed to the restraint stress. The PRL levels after stress were significantly less in the diabetic rats, indicating a blunted PRL stress response. These results indicate that the diabetic state can affect an animals PRL and CORT response to a new acute stress.     

Effect of acute swimming exercise on lactate levels and its relation with zinc in pinealectomized rats

It is argued that melatonin secreted from the pineal gland regulates the levels of zinc, which is an important trace element. Decreases in zinc levels of pinealectomized rats supports this relationship. There is an increasing amount of evidence suggesting that the pineal gland can have important effects on physical activity. The objective of the present study was to explore the changes in serum lactate levels in pinealectomized rats subjected to acute swimming exercise and its relation with zinc. Forty adult male rats of Spraque Dawley strain were equally allocated to four groups. Group 1: General Control Group. Group 2: Pinealectomized Control Group. Group 3: Swimming Control Group. Group 4: Pinealectomized Swimming Group. Serum zinc, melatonin and lactate levels were determined in the blood samples collected from the animals by a decapitation method. Zinc and melatonin levels were higher in Group 1 than in Groups 2, 3 and 4 (p < 0.01), higher in Group 3 than in Groups 2 and 4 (p < 0.01) and higher in Group 2 than in Group 4 (p < 0.01). The highest lactate levels were found in Group 4 (p < 0.01). Lactate levels in Group 3 were higher than those in Groups 1 and 2 (p < 0.01), while the levels in Groups 1 and 2 did not differ. Pinealectomy results in a significant increase in lactate levels in rats subjected to an acute swimming exercise. This increase in lactate levels may be associated with the decrease observed in zinc levels after pinealectomy.     

Effect of hyperthermia on epididymal cyclic AMP levels in diabetic non-diabetic and hypophysectomized rats.

The effect of elevated body temperatures on the concentrations of epididymal cyclic AMP levels in non-diabetic, diabetic and hypophysectomized rats was studied. Cyclic AMP levels were increased during hyperthermia in all animals examined. This increase in epididymal cyclic AMP concentration was not seen in animals that had been supplemented with exogenous insulin prior to the experiment. The effect of pituitary lipolytic hormones on epididymal cyclic AMP levels was also investigated. Significant elevations of epididymal cyclic AMP levels were observed in hypophysectomized rats during hyperthermia indicating that pituitary hormones are not essential in causing these increases. Extrapituitary hormones, such as glucagon, might be responsible for epididymal cyclic AMP increases. Increases in epididymal cyclic AMP levels may therefore be the result of the reduction of blood insulin and concomitant increases of lipolytic hormones of both pituitary and extrapituitary origins.     

Extracellular HSP70 levels in diabetic environment in rats

The expression of HSP70 in embryonic cells of mammals and its role for their normal development and protection is an important aspect to be investigated in pregnancy and/or mild diabetes. In this sense, the present study evaluated the effects of mild diabetes on maternal reproductive parameters and HSP70 levels in Wistar rats at different stages of life and in their offspring. Mild diabetes was induced by a beta-cytotoxic drug (streptozotocin) at birth. Four experimental groups were evaluated: at 90 days of age: nonpregnant nondiabetic (ND90) and nonpregnant mild diabetic (D90) female rats, and at term pregnancy: pregnant female rats of both glycemic status were examined (NDP and DP, respectively). The rats were submitted to oral glucose tolerance test, and blood samples were collected for determination of HSP70 levels. In addition, the reproductive performance of pregnant rats was assessed and HSP70 levels determined in their offspring blood samples. The HSP70 levels and maternal reproductive performance presented no difference between ND and D rats, regardless of the life stage. The HSP70 levels were increased in D90 rats and lower in offspring from D rats. Maternal HSP70 levels were positively correlated to the number of dead embryos. In conclusion, mild diabetes did not affect maternal reproductive performance, but high maternal HSP70 levels compromised embryo development. In addition, offspring from D rats exhibited lower HSP70 levels, showing that this protein can be used as an indicator of metabolic consequences of diabetes and predictor of related disorders in adulthood.     

Optimization of sodium orthovanadate to treat streptozotocin-induced diabetic rats

Oral administration of sodium orthovanadate restored blood glucose to normal levels in streptozotocin-induced diabetic rats. To establish the safety dose and to evaluate the side effects of over dose, if any, different doses of vanadium were used in the present study. Low concentrations of vanadium (0.1 and 0.3 mg/ml in drinking water) restored blood glucose, urea, cholesterol and the status of liver pathophysiological enzymes to normal levels in experimental rats. High vanadate treatment proved to be toxic not only to diabetic but also to normal rats as evidenced from the observations on the blood urea, plasma and liver glutamate oxaloacetate transaminase and glutamate pyruvate transaminase. Low vanadate treatment restored body homeostasis of diabetic rats and was found to be nontoxic to normals.     

黄连素对糖尿病大鼠胰岛素抵抗的治疗作用

目的:探讨黄连素对链脲佐菌素所致糖尿病大鼠胰岛素抵抗的治疗作用。方法:采用链脲佐菌素腹腔注射的方式建立大鼠糖尿病模型,将实验大鼠分为5组:分别为模型组、黄连素低(100 mg/kg)、黄连素中(200 mg/kg)、黄连素高(300 mg/kg)剂量组和阳性对照组(二甲双胍:50 mg/kg),每组10只。另取10只正常大鼠作为正常组。黄连素低、中、高剂量组小鼠每天分别灌胃100、200和300 mg/kg黄连素;对照组每天灌胃二甲双胍50 mg/kg;正常组和模型组每天给予相同体积的生理盐水进行灌胃; 1次/天,连续灌胃4周。通过测定大鼠血FBG、果糖胺水平,OGTT实验,胰岛素(FINS)水平,并计算大鼠胰岛素抵抗指数(HOMA-IR)来评价黄连素对糖尿病大鼠胰岛素抵抗作用。结果:与正常组相比,给药前模型组大鼠静脉血FBG含量显著升高(P<0.05);与模型组比较,给药2周及以后给药4周后阳性对照组、黄连素中剂量组和高剂量组大鼠静脉血FBG含量均显著下降(P<0.05);给药4周后,阳性对照组、黄连素低、中、高剂量组OGTT实验结果显示在不同时间节点的血糖值均显著低于模...     

Effect of kolaviron on islet dynamics in diabetic rats

Kolaviron, a biflavonoid isolated from the edible seeds of Garcinia kola, lowers blood glucose in experimental models of diabetes; however, the underlying mechanisms are not yet fully elucidated. The objective of the current study was to assess the effects of kolaviron on islet dynamics in streptozotocin-induced diabetic rats. Using double immunolabeling of glucagon and insulin, we identified insulin-producing β- and glucagon-producing α-cells in the islets of diabetic and control rats and determined the fractional β-cell area, α-cell area and islet number. STZ challenged rats presented with islet hypoplasia and reduced β-cell area concomitant with an increase in α-cell area. Kolaviron restored some islet architecture in diabetic rats through the increased β-cell area. Overall, kolaviron-treated diabetic rats presented a significant (p < 0.05) increase in the number of large and very large islets compared to diabetic control but no difference in islet number and α-cell area. The β-cell replenishment potential of kolaviron and its overall positive effects on glycemic control suggest that it may be a viable target for diabetes treatment.