Diurnal secretion of ghrelin, growth hormone, insulin binding proteins, and prolactin in normal weight and overweight subjects with and without the night eating syndrome

• Published in: Appetite Vol. 59; no. 3; pp. 688 - 692
• Main Authors: Birketvedt, Grethe S., Geliebter, Allan, Kristiansen, Ingrid, Firgenschau, Yngve, Goll, Rasmus, Florholmen, Jon R.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2012
• Subjects: Adult; Aged; Anorexia - blood; Circadian Rhythm - physiology; Feeding Behavior - physiology; Female; Ghrelin - blood; Ghrelin - secretion; Gut-brain axis; Human Growth Hormone - blood; Human Growth Hormone - secretion; Humans; Hyperphagia - blood; Insulin-Like Growth Factor Binding Protein 1 - blood; Insulin-Like Growth Factor Binding Protein 1 - secretion; Insulin-Like Growth Factor Binding Protein 3 - blood; Insulin-Like Growth Factor Binding Protein 3 - secretion; Insulin-Like Growth Factor Binding Proteins - blood; Insulin-Like Growth Factor Binding Proteins - secretion; Middle Aged; Overweight; Overweight - blood; Overweight - complications; Overweight - physiopathology; Postprandial; Prolactin - blood; Prolactin - secretion; Reference Values; Sleep; Sleep Initiation and Maintenance Disorders - blood; Syndrome; Postprandial; Gut-brain axis; Overweight
• ISSN: 0195-6663; 1095-8304
• DOI: 10.1016/j.appet.2012.07.015

► Diurnal secretion of ghrelin in night eaters and controls. ► Diurnal secretion of growth hormone in night eaters and controls. ► Diurnal secretion of insulin binding proteins in night eaters and controls. ► Diurnal secretion of prolactin in night eaters and controls. The regulatory peptide ghrelin has been proposed to help mediate both hunger and sleep. The neuroendocrine circadian patterns in the night eating syndrome (NES) have been distinguished by an attenuated nocturnal rise in the plasma concentrations of melatonin and leptin and a greater increase in the concentrations of cortisol. In this study we wanted to test the hypothesis that night eaters have disturbances in the circadian levels of ghrelin, growth hormone (GH) and associated regulatory peptides. In 12 female night eaters (6 normal weight and 6 overweight), and 25 healthy controls (12 normal weight and 13 overweight), blood was sampled over a 24-hour period. Four meals were served from 8 AM to 8 PM, and blood samples were drawn every second hour for determination of plasma ghrelin concentrations and GH by radioimmunoassay (RIA). Analysis of serum GH, IGF-1, IGFBP-3 and prolactin were performed by ELISA. In healthy normal weight subjects there was a slight but non significant nocturnal increase of ghrelin, whereas a more or less flat curve was observed for healthy overweight, NES normal weight and NES overweight patients. The RMANOVA analysis showed a significant independent lowering effect of overweight on the grand mean of ghrelin. No direct effects on NES normal weight and overweight subjects were found, but a near-significant interaction was found between healthy overweight and overweight NES subjects. There were independent significant lowering effects of overweight and NES on the serum GH levels. During the time course no changes in the serum levels of IGF-1 or IGFB-3 were observed. Independent significant lowering effects of overweight and NES on the levels of IGF-1 were detected, whereas a near significant reduction in the global levels of IGFBP-3 was observed in both NES groups. Finally, significant nocturnal changes were observed for serum levels of prolactin in all four subgroups. Grand mean levels tended to be higher in NES subjects whereas the opposite was observed in healthy overweight (ns). We conclude that in both NES groups and in healthy overweight subjects more or less attenuated ghrelin and GH secretions were observed, whereas divergent secretions were observed for prolactin.