Effects of exercise and metformin on the prevention of glucose intolerance: a comparative study

We aimed to evaluate the effects of aerobic exercise training (4 days) and metformin exposure on acute glucose intolerance after dexamethasone treatment in rats. Forty-two adult male Wistar rats (8 weeks old) were divided randomly into four groups: sedentary control (SCT), sedentary dexamethasone-treated (SDX), training dexamethasone-treated (DPE), and dexamethasone and metformin treated group (DMT). Glucose tolerance tests and in situ liver perfusion were undertaken on fasting rats to obtain glucose profiles. The DPE group displayed a significant decrease in glucose values compared with the SDX group. Average glucose levels in the DPE group did not differ from those of the DMT group, so we suggest that exercise training corrects dexamethasone-induced glucose intolerance and improves glucose profiles in a similar manner to that observed with metformin. These data suggest that exercise may prevent the development of glucose intolerance induced by dexamethasone in rats to a similar magnitude to that observed after metformin treatment.

Antioxidant and anti hyperglycemic role of wine grape powder in rats fed with a high fructose diet

BACKGROUND: Metabolic syndrome is a growing worldwide health problem. We evaluated the effects of wine grape powder (WGP), rich in antioxidants and fiber, in a rat model of metabolic syndrome induced by a high fructose diet. We tested whether WGP supplementation may prevent glucose intolerance and decrease oxidative stress in rats fed with a high fructose diet. METHODS: Male Sprague-Dawley rats weighing 180 g were divided into four groups according to their feeding protocols. Rats were fed with control diet (C), control plus 20 % WGP (C + WGP), 50 % high fructose (HF) or 50 % fructose plus 20 % WGP (HF + WGP) for 16 weeks. Blood glucose, insulin and triglycerides, weight, and arterial blood pressure were measured. Homeostasis model assessment (HOMA) index was calculated using insulin and glucose values. A glucose tolerance test was performed 2 days before the end of the experiment. As an index of oxidative stress, thio-barbituric acid reactive substances (TBARS) level was measured in plasma and kidney, and superoxide dismutase was measured in the kidney. RESULTS: Thiobarbituric acid reactive substances in plasma and renal tissue were significantly higher when compared to the control group. In addition, the area under the curve of the glucose tolerance test was higher in HF fed animals. Furthermore, fasting blood glucose, plasma insulin levels, and the HOMA index, were also increased. WGP supplementation prevented these alterations in rats fed with the HF diet. We did not find any significant difference in body weight or systolic blood pressure in any of the groups. CONCLUSIONS: Our results show that WGP supplementation prevented hyperglycemia, insulin resistance and reduced oxidative stress in rats fed with HF diet. We propose that WGP may be used as a supplement in human food as well.

[Evaluation of the effect of dehydroepiandrostrone [DHEA] on insulin sensitivity in IGT patients]

Dehydroepiandrostrone [DHEA] is one of three adrenal hormones and the most abundant estroid hormone in the body. Compared to other adrenal hormones, it decreases with advancing age, being 10-20% in the seventies, hence it is called the fountain of youth. Recently DHEA has been noticed for many of its effects including its antidepressant, protective effect on neuron injuries, effect on the hypocampaus and vascular endotheliurn, and its effects on autoimmune disease such as Lupus and ulcerative colitis; there is however controversy regarding its effects on insulin sensitivity. Based on glucose tolerance tests, subjects were selected from among patients, attending the Isfahan endocrine research center; 30 IGT patients by cross-over were treated with DHEA or placebo for six months and insulin sensitivity at the beginning and the end of treatment were compared. In the first three months, the mean changes in the drug group were: DHEA-S 94micro g/dL [P-value0.008], HOMA-IR 0.62 [P-value 0.6], insulin 1 micro lU/mL [P-value 0.3], FBS 10.5 mg/dL [P-value 0.1] and changes in placebo group were: DHEA-S 2.5 [P-value 0.6], HOMA-IR 0.9 [P-value 0.03], FBS 15.5 [P-value 0.1], insulin 3.5 [P-value 0.05]. In the second three months, the mean changes in the drug group were: DHEA-S 166 micro g/dL, FBS 4.6 mg/dL, insulin 0.6 micro lU/mL, HOMA-IR 0.2, while changes in the placebo group were: DHEA-S 25, FBS 5.8, insulin 1.5, HOMA-IR 0.6. This study showed that the treatment with DHEA did not improve insulin sensitivity, but probably is effective in preventing increase in insulin resistance

Prevention of type 2 diabetes in the prediabetic population.

Prevention of diabetes has been tried by several groups with varying degree of success. Prediabetic population are the ideal target for the purpose. In this study, prediabetic subjects are selected from the high-risk groups, like those having obesity, family history of diabetes, past history of gestational diabetes, hypertension, dyslipidaemia; and are included in the study when their fasting plasma glucose was found to be below 110 mg/dl and 2 hours postglucose (75g) plasma glucose remained between 110 and 200 mg/dl. After giving advice for lifestyle changes to all for a period of 3 months, those who had their blood glucose values in the impaird glucose tolerance (IGT) range were given either metformin, rosiglitazone or acarbose, the rest continued with diet and exercise only. Total follow-up period was 3 years. All groups maintained blood sugar in the euglycaemic range till the end of the 3-year period.