Dorsomedial hypothalamic corticotropin-releasing factor mediation of exercise-induced anorexia

Abstract

Running wheel access and resulting voluntary exercise alter food intake and reduce body weight. The neural mechanisms underlying these effects are unclear. In this study, we first assessed the effects of 7 days of running wheel access on food intake, body weight, and hypothalamic gene expression. We demonstrate that running wheel access significantly decreases food intake and body weight and results in a significant elevation of CRF mRNA expression in the dorsomedial hypothalamus (DMH) but not the paraventricular nucleus. Seven-day running wheel access also results in elevated arcuate nucleus and DMH neuropeptide Y gene expression. To assess a potential role for elevated DMH CRF activity in the activity-induced changes in food intake and body weight, we compared changes in food intake, body weight, and hypothalamic gene expression in rats receiving intracerebroventricular (ICV) CRF antagonist alpha-helical CRF or vehicle with or without access to running wheels. During a 4-day period of running wheel access, we found that exercise-induced reductions of food intake and body weight were significantly attenuated by ICV injection of the CRF antagonist. The effect on food intake was specific to a blockade of activity-induced changes in meal size. Central CRF antagonist injection further increased DMH CRF mRNA expression in exercised rats. Together, these data suggest that DMH CRF play a critical role in the anorexia resulting from increased voluntary exercise.

The effects of high-intensity intermittent exercise training on fat loss and fasting insulin levels of young women

“…11 For example, HIIE may have suppressed appetite or decreased attraction for energy-dense foods. 24,25 Another explanation for the HIIE fat loss effects is that this type of exercise may result in enhanced lipid utilization. Prior research in our laboratory has shown that lipid release, as indicated by blood glycerol levels, gradually increased over 20 min of HIIE.…”

The physiological and behavioral effects of subchronic intracisternal administration of TGF-β in rats: comparison with the effects of CRF

“…The increase in the concentration of TGF-β in CSF or expression of CRF mRNA in the brain is elicited by a common cause, i.e., exercise, which is one of the physical stressors (15,19,30). A large number of studies have reported the physiological and behavioral effects of CRF.…”

“…It is well known that exercise, which is a stressor, elicits increased expression of CRF in the brain (15,19,30). Many researchers have examined CRF in relation to stress in detail and have demonstrated that CRF initiates biological response to stress via the HPA axis and sympathetic nervous system (3).…”

Effects of long-term forced exercise training on body mass, energy metabolism and serum leptin levels inApodemus chevrieri(Mammalia: Rodentia: Muridae)

“…However, most previous research on the effects of exercise training on body mass focused on experimental rats (Levin & Dunn-Meynell 2004;Kawaguchi et al 2005). Little attention was paid to wild rodents.…”