The effect of exercise intensity on plasma and tissue acyl ghrelin concentrations in fasted rats.
OBJECTIVE
This study was conducted to investigate the effect of exercise training and feeding status on plasma and tissue acyl ghrelin concentrations.


METHODS
Thirty-two, eight-week-old male Wistar rats (185±5g) were randomly assigned to one of four groups: high intensity (HI: 34 m/min ~80-85% VO(2)max), moderate intensity (MI: 28 m/min ~70-75% VO(2)max), low intensity (LI: 20 m/min ~50-55% VO(2)max), and sedentary control (SED) groups. All experimental groups performed a 12-week exercise program consisting of treadmill running on a 0° slope for 1 h/day, 5 days/week at their respective training intensity. Twenty four hours following the last training session the animals completed a 12h fast. Rats were then killed, blood was collected and plasma separated; the fundus and soleus muscle were excised and frozen in liquid nitrogen for later analysis. Fasting levels of circulating acyl ghrelin and acyl ghrelin content in the soleus muscle and fundus, as well as glycogen in the soleus muscle were measured. Data were analyzed using one-way ANOVA.


RESULTS
Results demonstrated that 12 weeks of exercise training combined with a 12h fast significantly increased plasma as well as soleus muscle concentrations of acyl ghrelin in the HI and MI groups (p<0.05) and reduced acyl ghrelin concentrations in the fundus (p<0.05).


CONCLUSIONS
The results of the study indicate that chronic treadmill exercise training enhances fasting plasma acyl ghrelin in an intensity-dependent manner which is accompanied by a significant increase in soleus muscle and reduction in fundus acyl ghrelin levels.
Fathi
Rozita
R
Department of Physical Education and Sport Science, University of Mazandaran, Babolsar, Iran.
Ghanbari-Niaki
Abbass
A
Kraemer
Robert R
RR
Talebi-Garakani
Elahe
E
Saghebjoo
Marziyeh
M
D000818:Animals; D005215:Fasting / Q000097:blood*; D054439:Ghrelin / Q000097:blood* / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
D054439:Ghrelin; D006003:Glycogen