Glucocorticoid antagonism limits adiposity rebound and glucose intolerance in young male rats following the cessation of daily exercise and caloric restriction.

Severe caloric restriction (CR), in a setting of regular physical exercise, may be a stress that sets the stage for adiposity rebound and insulin resistance when the food restriction and exercise stop. In this study, we examined the effect of mifepristone, a glucocorticoid (GC) receptor antagonist, on limiting adipose tissue mass gain and preserving whole body insulin sensitivity following the cessation of daily running and CR. We calorically restricted male Sprague-Dawley rats and provided access to voluntary running wheels for 3 wk followed by locking of the wheels and reintroduction to ad libitum feeding with or without mifepristone (80 mg·kg(-1)·day(-1)) for 1 wk. Cessation of daily running and CR increased HOMA-IR and visceral adipose mass as well as glucose and insulin area under the curve during an oral glucose tolerance test vs. pre-wheel lock exercised rats and sedentary rats (all P < 0.05). Insulin sensitivity and glucose tolerance were preserved and adipose tissue mass gain was attenuated by daily mifepristone treatment during the post-wheel lock period. These findings suggest that following regular exercise and CR there are GC-induced mechanisms that promote adipose tissue mass gain and impaired metabolic control in healthy organisms and that this phenomenon can be inhibited by the GC receptor antagonist mifepristone.

Current perspectives on physical activity and exercise for youth with diabetes.

Regular physical activity (PA) for youth with diabetes improves cardiorespiratory fitness, body composition, bone health, insulin sensitivity, and psychosocial well-being. However many youth with diabetes or pre-diabetes fail to meet minimum PA guidelines and a large percentage of youth with diabetes are overweight or obese. Active youth with type 1 diabetes tend to have lower HbA1c levels and reduced insulin needs, whereas activity in adolescents at-risk for type 2 diabetes improves various measures of metabolism and body composition. Insulin and nutrient adjustments for exercise in type 1 diabetes is complex because of varied responses to exercise type and because of the different times of day that exercise is performed. This review highlights the benefits of exercise and the established barriers to exercise participation in the pediatric diabetes population. A new exercise management algorithm for insulin and carbohydrate intake strategies for active youth with type 1 diabetes is presented.

Curcumin limits weight gain, adipose tissue growth, and glucose intolerance following the cessation of exercise and caloric restriction in rats.

Weight regain, adipose tissue growth, and insulin resistance can occur within days after the cessation of regular dieting and exercise. This phenomenon has been attributed, in part, to the actions of stress hormones as well as local and systemic inflammation. We investigated the effect of curcumin, a naturally occurring polyphenol known for its anti-inflammatory properties and inhibitory action on 11ß-HSD1 activity, on preserving metabolic health and limiting adipose tissue growth following the cessation of daily exercise and caloric restriction (CR). Sprague-Dawley rats (6-7 wk old) underwent a "training" protocol of 24-h voluntary running wheel access and CR (15-20 g/day; ~50-65% of ad libitum intake) for 3 wk ("All Trained") or were sedentary and fed ad libitum ("Sed"). After 3 wk, All Trained were randomly divided into one group which was terminated immediately ("Trained"), and two detrained groups which had their wheels locked and were reintroduced to ad libitum feeding for 1 wk. The wheel locked groups received either a daily gavage of a placebo ("Detrained + Placebo") or curcumin (200 mg/kg) ("Detrained + Curcumin"). Cessation of daily CR and exercise caused an increase in body mass, as well as a 9- to 14-fold increase in epididymal, perirenal, and inguinal adipose tissue mass, all of which were attenuated by curcumin ( P < 0.05). Insulin area under the curve (AUC) during an oral glucose tolerance test, HOMA-IR, and C-reactive protein (CRP) were elevated 6-, 9-, and 2-fold, respectively, in the Detrained + Placebo group vs. the Trained group (all P < 0.05). Curcumin reduced insulin AUC, HOMA-IR, and CRP vs. the placebo group (all P < 0.05). Our results indicate that curcumin has a protective effect against weight regain and impaired metabolic control following a successful period of weight loss through diet and exercise, perhaps via inhibition of glucocorticoid action and inflammation. NEW & NOTEWORTHY Weight regain after dieting and exercise is a common phenomenon plaguing many individuals. The biological mechanisms underlying weight regain are incompletely understood and are likely multifactorial. In this paper, we examined the metabolic implications of curcumin, a compound known for its anti-inflammatory properties and inhibitory action on the enzyme 11ß-HSD1, in a rodent model of adiposity rebound after the cessation of diet and exercise.