Appetite-Regulating Peptides Offer Clues to AN Subtypes

Peptides levels provide helpful clues.

The presence of certain peptides that regulate appetite may be helpful for differentiating subtypes of anorexia nervosa (AN), according to results of a French study.

Patients with AN and binge eating and purging behavior have a very different profile of appetite regulatory peptides when compared with those with the purely restrictive type of AN, according to Dr. Bruno Estour and his colleagues at Centre Hospitalier Universitaire Saint Etienne in France (J Clin Endocrinol Metab 2010; 95: 3057).

The authors’ cross-sectional study included four groups of age-matched young women: 22 who exhibited food restriction; 10 with associated binge eating-purging behavior; 16 normal-weight bulimia nervosa (BN) patients, and 9 healthy controls. The researchers determined the circadian profiles of the orexigenic hormone ghrelin, the putative anorexigenic hormone obestatin, and the anorexigenic hormone peptide YY (PYY).

Dr. Estour and colleagues found that total and acylated ghrelin and obestatin circadian levels (measured 12 times in 24 hours) were higher in the food-restriction group than in controls, but significantly lower than controls in both the binge eating-purging and bulimia groups. The authors noted that the ghrelin and obestatin profiles of binge-purge patients were identical to those of normal-weight subjects with BN, suggesting that bingeing-purging behavior strongly modifies the homeostatic aspects of food restriction.

Levels of the gut peptide PYY, on the other hand, were lower in all three categories of eating disorders than in controls. The authors suggest that PYY could be as a common marker for appetite dysregulation in persons with eating disorders.

In binge-purging anorexia nervosa (AN) and BN patients, the acylated-to-total ghrelin ratio was significantly decreased, whereas ratios of obestatin to acylated ghrelin and PYY to acylated ghrelin were increased in both groups with bingeing-purging behavior.

The authors concluded that very low ghrelin levels and increased anorexigenic:orexigenic peptide ratios suggest either a lack of adaptation to a starvation state or a higher ability to cope with malnutrition. They concluded that the results of their study highlight the potential value of adding biological markers like ghrelin (and possibly obestatin) to classification of some eating disorders.