Serum Acylated Ghrelin Concentrations in Response to Short-Term Overfeeding in Normal Weight, Overweight, and Obese Men

Abstract

BackgroundGhrelin, an orexigenic gut hormone secreted primarily from the stomach, is involved in energy homeostasis. However, little data is available regarding its response to energy surplus and the development of human obesity.ObjectiveThe present study investigated the response of circulating acylated ghrelin to a 7-day positive energy challenge.DesignA total of 68 healthy young men were overfed 70% more calories than required, for 1-week. Subjects were classified based on percent body fat (measured by dual-energy X-ray absorptiometry) as normal weight, overweight, and obese. Serum acylated ghrelin concentration was measured before and after the positive energy challenge. Additionally, the relationship between acylated ghrelin and obesity-related phenotypes including weight, body mass index, percent body fat, cholesterol, HDL-c, LDL-c, glucose, insulin and homeostasis model assessment of insulin resistance and β-cell function at baseline and change due to overfeeding, were assessed.ResultsContrary to our expectations, serum acylated ghrelin was significantly increased in response to overfeeding and the increase was independent of obesity status. There was no significant difference in fasting acylated ghrelin between normal weight, overweight, and obese men at baseline. Acylated ghrelin was negatively correlated with weight and BMI for normal weight and with BMI in overweight men. Also ghrelin was correlated with change in weight and BMI in overweight (negative relationship) and obese (positive relationship) groups.ConclusionOur results showed that circulating acylated ghrelin was increased after a 7-day positive energy challenge regardless of adiposity status. However, acylated ghrelin was correlated with change in weight and BMI in opposing directions, in overweight and obese subjects respectively, thus dependent on obesity status.

The Relationship between Type 2 Diabetes and Total Ghrelin Level in a Population Sample in the United Arab Emirates

“…We found that ghrelin concentrations of patients with type 2 diabetes was significantly lower (P<0.05) than those of controls group which was in line with previous studies [7,[15][16][17]. Our findings support the view that low ghrelin level could have a causative role in the development of type 2 diabetes.…”

Circulating glucagon-like peptide-1 increases in response to short-term overfeeding in men

“…Changes in anthropometrics, body composition and measures of glucose and lipid metabolism were previously described by us [31,32,40]; nevertheless, it was evident that the one-week overfeeding challenge increased body weight, adiposity, serum lipids, insulin and insulin resistance. After a one week energy surplus, circulating GLP-1 concentration rose in the cohort.…”

Central acylated ghrelin improves memory function and hippocampal AMPK activation and partly reverses the impairment of energy and glucose metabolism in rats infused with β-amyloid

“…HOMA-IR, an indicator of insulin resistance, was much higher in AD-C rats than Non-AD-C rats and acyl-ghrelin prevented the increase in HOMA-IR experienced by AD-C and AD-DES-G (Table 2). Thus, rats in the AD-C group were insulin resistant, which was possibly associated with hippocampal deposition of β-amyloid [8], and central ghrelin infusion prevented the exacerbation of insulin resistance.…”

“…Furthermore, fasting serum ghrelin concentrations vary considerably and results are inconsistent in obese and normal weight people [7]. Serum ghrelin levels after glucose load and post-prandial states are not consistent with obesity [8][9][10], and there is some evidence that ghrelin release may be related to stress-induced eating behaviors and ethnicity [9,10].…”