Acylated Ghrelin Response to Acute Exercise in Obesity

Ghrelin is a GH-secretagogue gastrointestinal hormone that regulates feeding behavior by interacting directly with hypothalamic centers in concert with other negative and permissive neuromodulators. Ghrelin is involved in controlling energy balance in the short-term and long-term, and its levels are inversely related to the degree of obesity, insulin-resistance and energy accumulation. Consequently, obesity bears decreased ghrelin levels which increase upon weight loss, energy depletion and long-term exercise programs. Nevertheless, the role of acute exercise on the secretion of the bioactive component of ghrelin is yet unknown in conditions of normal and excessive body weight. Our study examines acylated and total ghrelin secretion following a cycloergometric exercise test in obese and age- and sex-matched lean subjects to document if ghrelin components change as a function of fat accumulation, insulin homeostasis, growth hormone secretion, non-esterified fatty acid availability and exercise performance. Our study aims at testing the hypothesis that ghrelin components may be regulated by acute exercise, with concentrations at the exercise peak being related to acute metabolic homeostasis. Targetting this purpose may help to clarify ghrelin involvement in acute conditions unrelated to gastrointestinal activities.