Significant lowering of plasma ghrelin but not des-acyl ghrelin in response to acute exercise in men

Abstract

Ghrelin, a 28-amino-acid peptide with n-octanoylation indispensable for binding to the growth hormone secretagogue receptor (GHS-R), was originally discovered in the human and rat stomach [1]. Ghrelin molecules are present as two major endogenous forms, an acylated form (ghrelin) and a des-acylated form (desacyl ghrelin). Ghrelin stimulates growth hormone (GH) Abstract. Ghrelin, an acylated peptide produced predominantly in the stomach, stimulates feeding and growth hormone (GH) secretion via interaction with the GH secretagogue receptor. Ghrelin molecules are present in two major endogenous forms, an acylated form (ghrelin) and a des-acylated form (des-acyl ghrelin). Recent studies indicated that aerobic exercise did not change plasma total ghrelin levels, however, dynamics of circulating ghrelin and des-acyl ghrelin during aerobic exercise remains unclear. The purpose of this study is to examine the effects of moderate intensity exercise on plasma ghrelin and des-acyl ghrelin concentrations, and to investigate the relationship between ghrelin molecules and other hormonal and metabolic parameters during exercise. Nine healthy males (25.2 ± 0.5 years) exercised for 60 min at 50% of their maximal oxygen consumptions. We measured the plasma concentrations of ghrelin, des-acyl ghrelin, GH, norepinephrine (NE), epinephrine (E), dopamine (DA), insulin, and glucose. Plasma ghrelin level significantly decreased during exercise, whereas plasma des-acyl ghrelin and total ghrelin levels did not change. Plasma NE, E, DA and GH levels were significantly increased during exercise. Plasma insulin level significantly decreased during exercise, and plasma glucose levels remained steady during exercise. NE, E, DA, and GH were correlated negatively with plasma ghrelin levels. These findings suggest that acute moderate exercise may suppress ghrelin release from the stomach, decrease ghrelin O-acyltransferase activity, and/or activate ghrelin utilization in peripheral tissues and that exercise-induced ghrelin suppression may be mediated by activated adrenergic system.

Insulin Pump Therapy – Influence on Body Fat Redistribution, Skeletal Muscle Mass and Ghrelin, Leptin Changes in T1D Patients

“…Reduced ghrelin concentration after acute moderate intensity exercise might be due to increased sympathetic nervous system activity and decreased perfusion of gastric mucosa resulting from redistribution of blood flow from the splanchnic circulation towards the skeletal muscles during exercise [41]. The effects of exercise on ghrelin are rather controversial and depend on the intensity and duration of exercise [42, 43]. …”

Effects of Long Acting Methylphenidate on Ghrelin Levels in Male Children with Attention Deficit Hyperactivity Disorder: An Open Label Trial

“…In patients with anorexia nervosa, this altered activity of the dopamine system due to the increase of ghrelin may be involved not only in hyperactivity but also in aberrant cognitive processing related to food 85 . In response to acute physical exercise, plasma ghrelin levels tend to decrease 86 . The decreased hyperactivity of children with successful treatment by methylphenidate in this study might have had an effect on ghrelin levels.…”

Pathophysiologic Basis of Anorexia: Focus on the Interaction between Ghrelin Dynamics and the Serotonergic System

“…However, there are several reports showing that plasma ghrelin levels did not change or even decreased with exposure to stresses. For example, a recent study by Zimmerman and colleagues 40) has revealed that plasma ghrelin levels of men of normal weight subjected to the Trier Social Stress Test did not change when cortisol levels increased. Moreover, ghrelin levels decreased after drinking alcohol.…”