The Effect of Treadmill Running on Plasma and Muscle Agouti-Related Protein (AGRP) Concentration in Male Rats

Appetite regulation is one of the most important issues in exercise physiology. AGRP is one of the most important neuropeptide in appetite regulation and energy homeostasis. The aim of this study was to investigate the effect of treadmill running on plasma and muscle (Soleus) concentration of AGRP in male Wistar rats. Forty rats were randomly assigned into two groups. The training group was given exercise on a motor-driven treadmill at 28 m/min (equal to 75% vo2max) for 60 min/day, 5 days/week for 10 weeks. After finishing the exercise protocol, each group was divided into 2 subgroups, the fasting and the fed (n=10) groups. Each subgroup was anesthetized and sacrificed after an overnight fast and the other, after 3 hours of food deprivation. The results showed muscle and plasma AGRP were significantly (P < 0.001) higher in the trained rats in comparison to the control rats. Also there was a significant and positive correlation between Soleus AGRP and plasma AGRP. It can be speculated that negative energy balance as well as local hyperphagia in muscle, induced by exercise produces satiety, signals the hypothalamus, which therefore increases release of AGRP facilitating energy recovery. This mechanism may be involved in glycogen supercompensation as well.