Role of ghrelin in the regulation of energy balance in adult male albino rats

Abstract

Background Ghrelin is a 28-amino acid acylated peptide that was recently identified as endogenous ligand for growth hormone secretagogue receptor. It is a potent orexigenic peptide that stimulates food intake, adipogenesis, and body weight gain. However, its physiological role in the regulation of energy homeostasis is still controversial. Aim The study was performed to show the physiological role of ghrelin in energy balance and body weight homeostasis through assessing the effect of obesity and undernutrition on the plasma ghrelin level. Materials and methods Twenty-four adult male albino rats weighing 140–190 g were divided into three groups: group I (control group): rats of this group were given free access to food and water, group II (induction of obesity): rats of this group were fed a high-caloric diet for induction of obesity, and group III (chronic food restriction): rats of this group were fed by 30% of the diet consumed by the control group. Results The body weight is significantly increased in rats, which fed a high-caloric diet for induction of obesity, whereas plasma ghrelin level was significantly decreased. Food-restricted rats showed significantly decreased body weight and significantly elevated plasma ghrelin level. Conclusion These findings suggest that ghrelin has a pivotal role in mediating the physiological responses to undernutrition and overnutrition. Changes in the circulating level of ghrelin can represent an adaptative response to prevent long-lasting alterations in the energy balance and body weight.