Background. Several lines of evidence indicate a role of the brain-derived neurotrophic factor (BDNF) in the modulation of eating behaviour. Therefore, alterations in the physiology of this neurotrophin may be involved in the pathogenesis of eating disorders. In the present study, we investigated serum levels of BDNF in patients with anorexia nervosa (AN), bulimia nervosa (BN) and binge-eating disorder (BED).Method. Ninety-nine drug-free women (27 with AN, 24 with BN, 24 with BED and 24 healthy controls) underwent both a blood sample collection in the morning and diagnostic and psychopathological assessments by means of structured clinical interviews and ad-hoc rating scales. Serum levels of BDNF, 17β-oestradiol, FT3 and FT4 were measured.Results. Compared to healthy controls, serum levels of BDNF were significantly reduced in underweight AN women and in normal weight BN women, but not in overweight BED women. Changes in circulating BDNF levels were not affected by the presence of co-morbid depressive disorders. No significant correlation emerged between neurotrophin concentrations and psychopathological, nutritional, demographic and hormonal variables.Conclusions. These findings evidentiate alterations in serum BDNF levels in malnourished patients with AN or BN, but not in well-nourished individuals with BED. Since BDNF seems to exert a satiety effect, its reduction may represent an adaptive change to counteract the decreased calorie ingestion of AN and BN individuals.

Background. Ghrelin and leptin are endogenous peripheral proteins involved in the regulation of eating behaviour. In particular, ghrelin stimulates hunger and promotes food ingestion, whereas leptin increases satiety and reduces food consumption. Therefore, alterations in the physiology of these peptides may play a role in the pathogenesis of eating disorders such as bulimia nervosa. In the present study, we investigated ghrelin and leptin responses to food ingestion in patients with bulimia nervosa.Method. Nine symptomatic drug-free bulimic women and 12 age-matched healthy women ingested a meal of 1207 kcal (60% carbohydrates, 23% fat and 17% proteins) at 12.00 a.m. and underwent blood sample collection before and 45, 60, 90, 120 and 180 min after the meal. Plasma levels of ghrelin, leptin, insulin and glucose were measured.Results. In healthy women, circulating ghrelin exhibited a drastic decrease after the food intake whereas, in bulimic patients, this response was significantly blunted. No difference between the two subjects groups was observed in post-prandial profiles of plasma leptin, insulin and glucose.Conclusions. The lack of a leptin response to food ingestion, in both bulimic and healthy women, is compatible with the role of this peptide as long-term rather than short-term modulator of eating behaviour. The blunted ghrelin response to food ingestion may support the occurrence in bulimic subjects of an impaired suppression of the drive to eat following a meal. This may have implications for binge-eating.