Influence of eNOS gene polymorphism on cardiometabolic parameters in response to physical training in postmenopausal women

The health-promoting effects of exercise training (ET) are related to nitric oxide (NO) production and/or its bioavailability. The objective of this study was to determine whether single nucleotide polymorphism of the endothelial NO synthase (eNOS) gene at positions -786T>C, G894T (Glu298Asp) and at the variable number of tandem repeat (VNTR) Intron 4b/a would interfere with the cardiometabolic responses of postmenopausal women submitted to physical training. Forty-nine postmenopausal women were trained in sessions of 30-40 min, 3 days a week for 8 weeks. Genotypes, oxidative stress status and cardiometabolic parameters were then evaluated in a double-blind design. Both systolic and diastolic blood pressure values were significantly reduced after ET, which was genotype-independent. However, women without eNOS gene polymorphism at position -786T>C (TT genotype) and Intron 4b/a (bb genotype) presented a better reduction of total cholesterol levels (-786T>C: before = 213 ± 12.1, after = 159.8 ± 14.4, Δ = -24.9% and Intron 4b/a: before = 211.8 ± 7.4, after = 180.12 ± 6.4 mg/dL, Δ = -15%), and LDL cholesterol (-786T>C: before = 146.1 ± 13.3, after = 82.8 ± 9.2, Δ = -43.3% and Intron 4b/a: before = 143.2 ± 8, after = 102.7 ± 5.8 mg/dL, Δ = -28.3%) in response to ET compared to those who carried the mutant allele. Superoxide dismutase activity was significantly increased in trained women whereas no changes were observed in malondialdehyde levels. Women without eNOS gene polymorphism at position -786T>C and Intron 4b/a showed a greater reduction of plasma cholesterol levels in response to ET. Furthermore, no genotype influence was observed on arterial blood pressure or oxidative stress status in this population.

PRODUCTION of FREE RADICALS and CATALASE ACTIVITY DURING ACUTE EXERCISE TRAINING IN YOUNG MEN

Reactive oxygen species (ROS) are constantly produced by cells that promote cellular oxidative damage and are neutralized by an antioxidant system including superoxide dismutase, glutathione, peroxidase and catalase. Male volunteers were exercised for 20 minutes, three days (60, 70 and 80% of maximum heart rate). Catalase activity and plasma malondialdehyde concentration were measured. The mean age of the volunteers was 25 +/- 7 years, with body mass index 2 of 24.03 +/- 4.32 kg/m(2). Acute exercise training produced an increase of malondialdehyde concentration that was exercise intensity-dependent in young volunteers. However, catalase activity shows a great variability at baseline and the percentual of reduction was exercise intensity-independent in this particular population. Therefore, our study shows that acute cycling exercise promotes an increase of oxidative stress that was exercise intensity-dependent in young volunteers. Furthermore, the antioxidant system measured by catalase activity was effective to counterbalance the ROS production showing a saturation behavior at an intensity of 70% of maximum heart rate.

Hipothalamy-pituitary axis: Effects of physical training in rats administered with dexamethasone

Aim. To investigate the effects of physical training associated to dexamethasone administration in carbohydrate metabolism and adrenocorticotrophic hormone (ACTH) release. Materials and methods. Young Wistar rats were divided into four groups: sedentary control (CS), sedentary dexanzethasone (DxS), trained control (CT) and trained dexamethasone (DxT). The rats were submitted to swimming training associate to administration of dexamethasone for ten weekends. Before sacrifice the rats received Subcutaneous insulin to calculate the maximum decreased in blood glucose. Venous blood was sampled obtained at the end experiment period to determine glucose, insulin, free fatty acids (FFA) and ACTH. Gastrocnemius and liver tissue samples were used to determination glycogen, and adipose epididimal tissue was used to measured the weight. Results. Dexamethasone administration provoke insulin resistance and the physical training reverted this aspect. Training promoted increase in muscle and liver glycogen store and a high utilization of FFA. Moreover the dexamethasone provoke decreased of ACTH release in response to acute exercise, showing marked differences in the functioning of the hypothalamy pituitary-adrenal (HPA) axis between groups of rats. Conclusions. a) Low-dose of dexamethasone promote several side effects in metabolism intermediary and chronic exposure to steroid was associated with insulin resistance; b) the regular swimming exercise promoted increased insulin sensitiviry Therefore. exercise can override the dexametasone negative feedback of the HPA axis activation in rats.

Cardiac benefits of exercise training in aging spontaneously hypertensive rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Is gender crucial for cardiovascular adjustments induced by exercise training in female spontaneously hypertensive rats?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Exercise training in the aerobic/anaerobic metabolic transition prevents glucose intolerance in alloxan-treated rats

Background: Ninety percent of cases of diabetes are of the slowly evolving non-insulin-dependent type, or Type 2 diabetes. Lack of exercise is regarded as one of the main causes of this disorder. In this study we analyzed the effects of physical exercise on glucose homeostasis in adult rats with type 2 diabetes induced by a neonatal injection of alloxan. Methods: Female Wistar rats aged 6 days were injected with either 250 mg/ kg of body weight of alloxan or citrate buffer 0.01 M (controls). After weaning, half of the animals in each group were subjected to physical training adjusted to meet the aerobic-anaerobic metabolic transition by swimming 1 h/day for 5 days a week with weight overloads. The necessary overload used was set and periodically readjusted for each rat through effort tests based on the maximal lactate steady state procedure. When aged 28, 60, 90, and 120 days, the rats underwent glucose tolerance tests (GTT) and their peripheral insulin sensitivity was evaluated using the HOMA index. Results: The area under the serum glucose curve obtained through GTT was always higher in alloxan-treated animals than in controls. A decrease in this area was observed in trained alloxan-treated rats at 90 and 120 days old compared with non-trained animals. At 90 days old the trained controls showed lower HOMA indices than the non-trained controls. Conclusion: Neonatal administration of alloxan induced a persistent glucose intolerance in all injected rats, which was successfully counteracted by physical training in the aerobic/anaerobic metabolic transition. © 2008 Mota et al; licensee BioMed Central Ltd.

Endurance swimming periodized training in rats

The aim of this study was to develop an experimental protocol for endurance swimming periodization training in rats similar to high performance training in humans, and compare it to continuous training. Three groups of male Wistar rats (90 days old) were allocated to Sedentary Control (SC); Continuous Training (CT); and Periodized Experimental Training (PET) groups. PET and CT trained 5 days/week, over five weeks, CT: continuous training supporting a 5% body mass (bm) load for 40 min/day; PET: training subdivided into basic, specific, and taper periods, with overload changed daily (volume-intensity, continuous, and interval training). Total training overload was quantified (% bm X exercise time in training session) and equalized for the two trained groups. Glucose ([ 3H]2-deoxyglucose) uptake, incorporation to glycogen (synthesis), glucose oxidation (CO 2 production), and lactate production from [U- 14C]glucose by soleus muscle strips incubated in presence of insulin (100μU/mL) were evaluated 48h after the last training session. The load equivalent at 5.5mM blood lactate concentration ([La-5.5]) was determined in the incremental test. Lactate production was similar in all groups. PET presented higher glucose uptake (59%) than SC, and higher glycogen synthesis (51 and 22%) and glucose oxidation (147 and 178%) than SC and CT, respectively. CT presented higher glycogen synthesis rates (23%) than SC. Load [La-5.5] was similar between trained groups and higher than SC. PET presented higher values for glucose metabolism than CT and SC. These results open up new perspectives for studying training methods used in high performance sport through swimming exercise in rats.

Managing environmental training in organizations: Theoretical review and proposal of a model

Purpose: The aim of this work is to address the issue of environmental training in organizations, presenting a theoretical review on the subject and proposing a model that highlights the importance of this type of training for organizations. Design/methodology/approach: The paper presents a thorough, updated literature review, discusses typology and the best practices of environmental training, and presents a framework integrating environmental training and organizational results. Findings: A careful consideration allows identifying a significant theoretical gap related to the lack of theoretical references, best practices, and an alignment between environmental training and organizational results. To overcome this gap, a model was proposed that helps to manage the environmental training process in organizations. Research limitations/implications: The paper needs to be complemented with empirical research on the topic. Originality/value: Environmental training is considered to be an essential element for organizations seeking to mitigate their environmental impacts. ISO 14001 states that environmental management is a duty of certified organizations. However, there have been few published articles that suggest models and insights to improve the environmental training in organizations. © Emerald Group Publishing Limited.