Research report Diurnal secretion of ghrelin, growth hormone, insulin binding proteins, and prolactin in normal weight and overweight subjects with and without the night eating syndrome q Grethe S. Birketvedt a,b,⇑ , Allan Geliebter c , Ingrid Kristiansen a , Yngve Firgenschau d , Rasmus Goll a , Jon R. Florholmen a a Research Group of Gastroenterology and Nutrition, University of Tromsø and University Hospital North Norway, 9037 Tromsø, Norway b Center of Bariatric Surgery and Morbid Obesity, Oslo University Hospital, Aker Hospital, Norway c St. Luke’s Hospital and Columbia University, New York City, USA d Department of Clinical Biochemistry, University of Tromø and University Hospital North, 9037 Tromsø, Norway article info Article history: Received 16 March 2012 Received in revised form 11 June 2012 Accepted 19 July 2012 Available online 27 July 2012 Keywords: Gut-brain axis Overweight Postprandial abstract The regulatory peptide ghrelin has been proposed to help mediate both hunger and sleep. The neuroen- docrine 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 concen- trations 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 over- weight), 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 over- weight 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. Indepen- dent 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, sig- nificant 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. Ó 2012 Elsevier Ltd. All rights reserved. Introduction Night eating syndrome (NES), characterized by morning anorex- ia, evening hyperphagia, and insomnia was first described in obese individuals in 1955 by Stunkard, Grace, and Wolf (1955). NES often develops during periods of stress and is associated with unsuccess- ful attempts at weight reduction. In 1999 Birketvedt et al. reported that night time awakenings were far more common among night eaters than among controls, and more than half of these awaken- ings were associated with food intake (Birketvedt et al., 1999). It is estimated that NES occurs in more than 1.5% of the general pop- ulation (Rand, Macgregor, & Stunkard, 1997). Moreover, NES has been found in 8.9% in an obesity clinic (Stunkard et al., 1996), in 12% of the obese patients in a nutrition clinic (Stunkard, 1959) and in 27% and 26%, respectively in two samples of severely obese persons (Rand et al., 1997; Rand & Kuldau, 1993). However, NES is also found in normal weight individuals and in postoperative obes- ity surgery patients (Rand & Kuldau, 1993). 0195-6663/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.appet.2012.07.015 q Acknowledgements: We highly appreciate the laboratory support performed by Ingrid Christiansen at the Laboratory of Gastroenterology and Nutrition, Institute of Clinical Medicine, University of Tromsø, Norway. This study was supported by fundings from Research Fund of Gastroenterology, University Hospital of North Norway, Tromsø, Norway. Authors report no conflicts of interest. ⇑ Corresponding author. E-mail address: gsb42nor@aol.com (G.S. Birketvedt). Appetite 59 (2012) 688–692 Contents lists available at SciVerse ScienceDirect Appetite journal homepage: www.elsevier.com/locate/appet