Fat gain with physical detraining is correlated with increased glucose transport and oxidation in periepididymal white adipose tissue in rats

Dexamethasone-Induced Adipose Tissue Redistribution and Metabolic Changes: Is Gene Expression the Main Factor? An Animal Model of Chronic Hypercortisolism

Chronic hypercortisolism has been associated with the development of several metabolic alterations, mostly caused by the effects of chronic glucocorticoid (GC) exposure over gene expression. The metabolic changes can be partially explained by the GC actions on different adipose tissues (ATs), leading to central obesity. In this regard, we aimed to characterize an experimental model of iatrogenic hypercortisolism in rats with significant AT redistribution. Male Wistar rats were distributed into control (CT) and GC-treated, which received dexamethasone sodium phosphate (0.5 mg/kg/day) by an osmotic minipump, for 4 weeks. GC-treated rats reproduced several characteristics observed in human hypercortisolism/Cushing’s syndrome, such as HPA axis inhibition, glucose intolerance, insulin resistance, dyslipidemia, hepatic lipid accumulation, and AT redistribution. There was an increase in the mesenteric (meWAT), perirenal (prWAT), and interscapular brown (BAT) ATs mass, but a reduction of the retroperitoneal (rpWAT) mass compared to CT rats. Overexpressed lipolytic and lipogenic gene profiles were observed in white adipose tissue (WAT) of GC rats as BAT dysfunction and whitening. The AT remodeling in response to GC excess showed more importance than the increase of AT mass per se, and it cannot be explained just by GC regulation of gene transcription.

Effects of exercise cessation on adipose tissue physiological markers related to fat regain: A systematic review

Tissues usually super compensate during the period that follow physical exercise. Although this is widely accepted for muscle and glycogen, the compensatory effect is not usually applied to fat tissues. Notwithstanding, evidence for this has been present since the 1970s when it was first suggested that the increased lipogenic activity in response to training might be an adaptation that enables to restore an energy reserve that can be used in times of need. In this context, the present review aimed to summarize information about the effect of detraining on fat metabolism and the physiological responses associated with fat regain. A systematic search on PubMed and Scielo was performed using "training cessation," "detraining," "exercise detraining," and "exercise cessation" combined with "fat tissue," "adipose tissue," "adipose metabolism," and "fat metabolism," as descriptors. From 377 results, 25 were included in this review, 12 humans and 13 rodents, resulting in a sample of 6772 humans and 613 animals. The analysis provided evidence for fat super compensation, as well as differences in humans and rodents, among different protocols and possible mechanisms for fat gain after exercise cessation. In summary, exercise cessation appears to increase the ability of the adipose tissue to store energy. However, caution should be taken, especially regarding conclusions based on investigations on humans, considering the multiple factors that could affect fat metabolism.

Exercise-Induced Regulation of Redox Status in Cardiovascular Diseases: The Role of Exercise Training and Detraining

Although low levels of reactive oxygen species (ROS) are beneficial for the organism ensuring normal cell and vascular function, the overproduction of ROS and increased oxidative stress levels play a significant role in the onset and progression of cardiovascular diseases (CVDs). This paper aims at providing a thorough review of the available literature investigating the effects of acute and chronic exercise training and detraining on redox regulation, in the context of CVDs. An acute bout of either cardiovascular or resistance exercise training induces a transient oxidative stress and inflammatory response accompanied by reduced antioxidant capacity and enhanced oxidative damage. There is evidence showing that these responses to exercise are proportional to exercise intensity and inversely related to an individual’s physical conditioning status. However, when chronically performed, both types of exercise amplify the antioxidant defense mechanism, reduce oxidative stress and preserve redox status. On the other hand, detraining results in maladaptations within a time-frame that depends on the exercise training intensity and mode, as high-intensity training is superior to low-intensity and resistance training is superior to cardiovascular training in preserving exercise-induced adaptations during detraining periods. Collectively, these findings suggest that exercise training, either cardiovascular or resistance or even a combination of them, is a promising, safe and efficient tool in the prevention and treatment of CVDs.

Benefits of aerobic training in girls with precocious puberty: involvement of CRP and cortisol

Background The aim of this study was to investigate the effect of 12 weeks of aerobic training, 4 weeks of detraining and use gonadotropin-releasing hormone agonist (GnRHa) on serum C-reactive protein (CRP) and cortisol levels in girls with central precocious puberty (CPP). Methods Forty-five girls (aged 6-8 years) with precocious puberty were randomly divided into three groups (medication, training and medicine + training groups). Fifteen healthy girls (without precocious puberty) were also included as the control group. Serum CRP and cortisol levels were measured at baseline by the enzyme-linked immunosorbent assay (ELISA) technique. Then, the experimental groups performed an aerobic training program for 3 days/week 20-75 min per day at 45-75% maximum heart rate for 12 weeks. The medication groups also received GnRHa during the study, once a month (1 mL every 4 weeks) by intramuscular injection. Serum CRP and cortisol levels were measured again 48 h after the last training session and also after 4 weeks of detraining. Results Analysis of variance (ANOVA) with repeated measures showed a significant decrease in CRP (p = 0.02) and cortisol levels (p = 0.01) in the training group and the medicine + training group. Detraining led to return of CRP and cortisol levels to the pre-training levels (p = 0.001). No significant difference in serum CRP (p = 0.43) and cortisol levels (p = 0.06) was observed in the medication group. Further, no significant difference was observed between groups in CRP and cortisol. Conclusions Long-term regular moderate training decreases inflammation indices, and detraining eliminates the benefits of training in girls with precocious puberty.

A Memory of Early Life Physical Activity Is Retained in Bone Marrow of Male Rats Fed a High-Fat Diet

Studies have reported opposing effects of high-fat (HF) diet and mechanical stimulation on lineage commitment of the bone marrow stem cells. Yet, how bone marrow modulates its gene expression in response to the combined effects of mechanical loading and a HF diet has not been addressed. We investigated whether early-life (before onset of sexual maturity at 6 weeks of age) voluntary physical activity can modulate the effects of a HF diet on male Sprague Dawley rats. In the bone marrow, early-life HF diet resulted in adipocyte hypertrophy and a pro-inflammatory and pro-adipogenic gene expression profile. The bone marrow of the rats that undertook wheel exercise while on a HF diet retained a memory of the early-life exercise. This memory lasted at least 60 days after the cessation of the voluntary exercise. Our results are consistent with the marrow adipose tissue having a unique response to HF feeding in the presence or absence of exercise.

Immediate and residual effects of low-dose nandrolone decanoate and treadmill training on adipose and reproductive tissues of male Wistar rats

CONTEXT

Residual effects after nandrolone decanoate (ND) treatment are not reported.

OBJECTIVE

Immediate and residual effects of low-dose ND and treadmill training were investigated.

MATERIALS AND METHODS

Male rats were trained and/or ND-treated for four weeks and the assessments were made after this period or four weeks later.

RESULTS

The groups did not differ in final plasma glucose or AUC of the ivGTT, but hyperinsulinemia was noticed in some trained/treated groups. Training with ND increased muscle mass and ND decreased the reproductive structures. Decreased fat with training was reversed by detraining.

DISCUSSION

The anabolic action of ND on skeletal muscle was enhanced by training. Fat and lipid changes were more linked to training/detraining, but the effects of ND on the reproductive structures persisted after treatment.

CONCLUSIONS

The effects of training on fat and muscle were not maintained after detraining, but low-dose ND had persistent effects on the reproductive structures.