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Does a failure to normalize diurnal glucocorticoids negate the benefits of exercise training?


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Does a failure to normalize diurnal glucocorticoids negate the benefits of exercise training?

 

Kevyn Mejia-Hernandez, Jon E. Campbell and Michael C. Riddell

 

School of Kinesiology and Health Science, York University, Toronto, Canada

 

ABSTRACT

 

Glucocorticoids (GCs) are released by the hypothalamic-pituitary-adrenal (HPA) axis in response to a variety of stressors. Although acute elevations of GCs are beneficial, prolonged exposure has significant and detrimental metabolic consequences, most notably seen in Cushing's syndrome. Here, we created an animal model of Cushing's syndrome and investigated the impact of exercise training on various metabolic parameters. Male Sprague-Dawley rats were divided into exercise and sedentary groups and further subdivided into control (SHAM) and corticosterone (CORT) groups. Exercising animals had access to running wheels for 6 weeks, while sedentary animals remained in standard cages. A 300mg corticosterone pellet was implanted subcutaneously in CORT rats while SHAM rats received a wax pellet. Within 1 week, both sedentary and exercising CORT rats demonstrated a {approx}15-and 1.7-fold elevation in nadir and peak GCs levels respectively, resulting in an abolished diurnal pattern. Relative to body weight, sedentary CORT animals had more epididymal fat when compared to sedentary controls. Conversely, exercise CORT rats had epididymal fat content comparable to that of exercise SHAM animals. This study proposes a new animal model of Cushing's syndrome and reveals that regular exercise attenuates the accumulation of visceral fat mass in this animal model. This study was funded by NSERC.

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WOW! What a good article..if I understand this, then, it means it makes no difference really~to exercise~ as far as adding fat to your body. If you have extra cortisol and a diurnal rhythym that is off..you will gain no matter what!

 

Isn't that what we already knew...sometimes, I wish they did not have to do scientific studies before they PROVE something....

 

we already have the proof right in our own bodies!!!!

 

Thanks for posting this!

LoriJane

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Did I misunderstand it, then? I thought the exercised rats with the steroid implant reduced the fat accumulation to the levels of the controls, whereas the steroid implanted sedentary rats had more fat accumulation?

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Did I misunderstand it, then? I thought the exercised rats with the steroid implant reduced the fat accumulation to the levels of the controls, whereas the steroid implanted sedentary rats had more fat accumulation?

 

Thats the way I read it, also. Both rat groups with cortisol gained but, the sed. rats gained the most. The cortisol exercising rats didn't gain any more fat than the control group. It is saying that we should exercise to keep the high cortisol from turning to fat. I will sign up for there human control group because I know that the opposite is true in me. The more I exercised the fatter I got. Didn't need any lab rat to tell me so either.

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