[Effect of twelve weeks of aerobic training on serum levels of leptin, vaspin and some indicators of oxidative stress in obese middle-aged women]

This study was conducted to determine the effect of twelve weeks of aerobic training on serum levels of leptin, vaspin, total antioxidant capacity [TAC] and malondialdehyde [MDA] in obese middle-aged women. In this quasi-experimental study, 30 sedentary, middle-aged women [mean +/- SD age 48.30 +/- 3.02 yr, body mass index 30.89 +/- 3.23 kg/m2 and body fat 32.88 +/- 2.71%] were randomized into the experimental [n=15] and control [n=15] groups. The experimental group performed twelve weeks aerobic training [3 times per week at an intensity of 65-75% of maximum heart rate reserve]. Blood samples were collected 24h before and 48h after the training. Data was analyzed by Student's t-test [P<0.05]. Results showed a significant decrease in serum levels of leptin and MDA [P values 0.009 and 0.01 respectively] while TAC significantly increased [P=0.01] in the experimental group. Body fat percentage significantly decreased in the experimental group [0.0001], but serum vaspin levels were not significantly different between the two groups [P=0.93]. Regular aerobic training is associated with weight loss and reduced body fat in obese women. As leptin production occurs in adipose tissue, subsequent decrease in body fat percent, serum leptin levels also occurred. On the other hand, aerobic training can improve oxidation/anti-oxidation in the body by reducing MDA concentration and increasing TAC

[Combined effect of aerobic training and Pistacia athlantica extract on GLUT-4 protein expression and muscle glycogen in diabetic rats]

The effects of exercise training on GLUT4 protein expression have been examined in several studies whereas those of aerobic training along with the use of plant extracts on muscle GLUT4 protein expression are unknown. The aim of the present study was to investigate the effects of aerobic training and Pistacia athlantica extract on GLUT4 protein expression and glycogen level in the gastrocnemius muscle of diabetic rats. Forty-male Wistar rats were randomly divided into five groups: Healthy control, diabetic control, diabetic+ aerobic training, diabetic+extract and diabetic+ aerobic training+ extract. The program included six weeks of aerobic training on the treadmill. Forty eight hours after last session of training and consumption the extract, the rats were anesthetized and gastrocnemius muscle was isolated for measurement of glycogen levels and GLUT4 protein expression. Data was analyzed by using one-way ANOVA test [P<0.05]. GLUT4 protein expression and glycogen levels in gastrocnemius muscle in diabetic+ aerobic training+ extract group were significantly higher than in the diabetic control group [P values 0.001, 0.02 respectively], whereas these variables in the aerobic training and the Pistacia athlantica extract perse groups did not change compared to the diabetic control group. It seems that Pistacia athlantica extract along with specific exercises, compared to utilization of each of strategies perse, are more effective in increasing glucose transporter proteins and possibly improving insulin function

[ influence of circuit resistance training intensity on ghrelin to obestatin ratio of plasma in healthy young women]

Ghrelin and obestatin are orexigenic and anorexigenic peptides, respectively, which are believed to be important in the regulation of energy homeostasis and body weight control. The purpose of this study was to clarify the possible mechanisms of resistance training in energy homeostasis and weight control. Twenty-seven female college students, age 22 +/- 1.54 yr, and body mass index 20.76 +/- 1.86 kg/m2 [mean +/- SE] were randomly assigned to the experimental and control groups. Subjects performed circuit-resistance training protocol with 40% and 80% 1 RM for 4 weeks. Circulating levels of total ghrelin, obestatin, ghrelin to obestatin ratio and glucose were measured before and after 4 weeks intervention for all subjects. One-way ANOVA revealed a higher and significant [P<0.05] post- training change in circulating levels of ghrelin to obestatin ratio as well as plasma obestatin concentrations significantly decreased [P<0.05] in the 80% IRM group. It seems that resistance training-induced energy deficit in the 80% IRM group resulted that ghrelin precursor goes to the production of ghrelin. Thus, obestatin secretion is reduced and ghrelin to obestatin ratio is increased to stimulate food intake behavior, compensating for lost energy sources and eventually restoring the body's energy balance

[Obestatin and the regulation of energy balance in physical activity]

Obestatin, a peptide which is encoded by the same preproghrelin gene as Ghrelin, conveys information concerning the nutritional status and/or the energy stores to the central nervous system. In obese populations, circulating levels of the peptide are altered. Ghrelin, mostly acting through the GH secretagogue receptor GHS-R, is a potent GH secretagogue, an orexigenic peptide and a long-term regulator of energy homeostasis. Obestatin was described for its anorexigenic effects and it's binding to GPR39. However recent studies do not support the role of obestatin/GPR39 system in the regulation of energy balance. Because exercise training improves the health status of obese individuals and is associated with reduction of body weight, there is growing interest in the effects of exercise on obestatin and whether this peptide may provide better understanding of how exercise improves health. Obestatin levels do not increase in response to acute exercise, and therefore obestatin does not appear to regulate growth hormone [GH] release during exercise. There is some evidence that obestatin levels do not change in plasma following resistance exercise with higher GH concentrations during exercise and decreases in tissues following chronic exercise but not in plasma. This review is focuses on obestatin, by first summarizing it function and it relationship with hormonal and metabolic changes that affect energy balance, and then discussing the effects of acute and chronic exercise on plasma and tissues obestatin concentrations, and the potential mechanisms involved

[Effects of circuit resistance training on plasma ghrelin levels in young women]

Ghrelin, an orexigenic peptide secreted from stomach mucosa, affects feeding behavior and plays an important role in energy balance and glucose homeostasis. Ample evidence indicates that resistance exercise is a key component of exercise recommendations for weight control. The purpose of the current study was to determine the effects of resistance training [4 weeks] on resting levels of plasma ghrelin, glucose, insulin and estrogen. Twenty-seven female college students, aged 221 +/- 1.54 years, height 162.66 +/- 5.05 cm, BMI 20.76 +/- 1.86 kg/m[2] and fat percent 20.95 +/- 2.08% [means +/- SE] were randomized into two, the experimental [40% and 80% 1RM] and the control groups. Subjects performed circuit-resistance exercise protocol with 40% and 80% 1RM, 4 d/wk for 4 weeks. Blood samples were collected 24 hours before and 48 hours after the training program. One-way ANOVA revealed that although no significant differences were observed in circulating levels of plasma total ghrelin [P=0.88], glucose [P=0.1] and insulin [P=0.66] in the experimental group when compared to the control group, a significant negative correlation [R=-0.4, P=0.05] was found between plasma estrogen and total ghrelin levels. It seems that because of a non significant increase in plasma ghrelin levels in the present study, there was no weight change of subjects during the training program and the short duration of the training program. However, the total ghrelin sub-fractions, acylated and non acylated, may have changed