Ghrelin and Obestatin Circadian Levels Differentiate Bingeing-Purging from Restrictive Anorexia Nervosa

Abstract

Abstract Context: Anorexia nervosa (AN) patients present with restrictive food behavior (AN-R). Some of them develop episodes of bulimia (AN-BP) without any clear pathophysiological explanation to date. Their clinical differentiation is important but not easily performed. Orexigenic/anorexigenic peptides measurements could provide some clues for that matter. Objective: The objective of the study was to determine whether the circadian profile of total and acylated ghrelin, obestatin, and peptide YY (PYY) levels is different in AN-R subjects when compared with AN-BP patients. Design and Settings: This was a cross-sectional study in an endocrinological unit. Patients and Control Subjects: Four groups of age-matched young women: 22 AN-R, 10 AN-BP, 16 normal-weight bulimia nervosa (BN), and nine controls. Main Outcome Measures: Twelve-point circadian profiles of plasma total and acylated ghrelin, obestatin, and PYY were measured. Results: Total and acylated ghrelin and obestatin circadian levels were increased in AN-R when compared with controls but decreased in both AN-BP and BN groups (P < 0.001). PYY was decreased in all groups with eating disorders. Acylated to total ghrelin ratio was decreased in AN-BP and BN (P < 0.001), whereas obestatin to acylated ghrelin and PYY to acylated ghrelin ratios were increased in both groups with bingeing-purging behavior (P < 0.0001). Conclusions: Patients with AN-associated bingeing-purging behavior present a very different profile of appetite regulatory peptides when compared with the pure restrictive type. The assessment of ghrelin (and eventually obestatin) could be of particular interest for differential diagnosis. Very low ghrelin levels and increased anorexigenic to orexigenic peptide ratios suggest either a lack of adaptation to a starvation state or a higher facility to cope with undernutrition.