Effects of Treadmill Exercise on Fundus Ghrelin Expression and Plasma Acylated Ghrelin level in Male Rats

The gastric peptide ghrelin, an endogenous ligand for growth-hormone secretagogue receptor, in its acylated form induces a positive energy balance, increase in food intake and adiposity.
This study aimed at determining the effects of treadmill exercise training on fundus Ghrelin mRNA expression, fundus, and plasma acylated Ghrelin concentration in rats. Materials and Methods: Thirty-six adult Wistar male rats (12-14 weeks old, 200-220g) were randomly divided into the experimental 1 (EX1) (n=16) and experimental 2 (EX2, n=20) groups with further division into control (n=8 and 10) and training (n=8 and 10) groups. Training groups were given exercise on a motor-driven treadmill (28 m/min, 0% grade, 60 min, 5 days/week for 8 weeks). Rats in EX1 were further divided into four groups; fed-control (FEC), fed-trained (FET), fast-control (FAT) and fast-trained (FAT). Twenty-four hours after last training session, the fundus was excised and frozen in liquid nitrogen for extraction of ghrelin mRNA. Fundus and plasma acylated ghrelin, growth hormone (GH), insulin, cortisol, lipids, and glucose were also measured. Results: Ghrelin mRNA expression was significantly (P=0.002) higher in fasted rats and lower in trained-rats, in whom a non significant increase was observed in resting plasma acylated Ghrelin, GH, insulin, liver glycogen and lower free fatty acids concentrations and muscle glycogen. Plasma cortisol, triglycerides (TG), total choles-Correspondence: Mehdi Hedayati, Obesity Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran E-mail: [email protected] (TC) was remained unchanged. Interestingly, fundus acylated ghrelin was significantly (P=0.031) lower in trained rats. Conclusion: The data obtained showed that treadmill exercise reduced ghrelin expression and its acylated levels in the fundus of trained rats and a higher plasma acylated ghrelin could be released from other source (s).