The
endocannabinoid system, consisting of two
cannabinoid receptors (CB1 and CB2) and the endogenous
ligands anandamide (
arachidonoylethanolamide (AEA)) and
2-arachidonoylglycerol (2-AG), has been shown to control food intake in both animals and humans, modulating either rewarding or quantitative aspects of the eating behavior. Moreover, hypothalamic
endocannabinoids seem to be part of neural circuitry involved in the modulating effects of
leptin on energy homeostasis. Therefore, alterations of the
endocannabinoid system could be involved in the pathophysiology of
eating disorders, where a deranged
leptin signalling has been also reported. In order to verify this hypothesis, we measured plasma levels of AEA, 2-AG, and
leptin in 15 women with
anorexia nervosa (
AN), 12 women with
bulimia nervosa (BN), 11 women with
binge-eating disorder (BED), and 15 healthy women. Plasma levels of AEA resulted significantly enhanced in both anorexic and BED women, but not in bulimic patients. No significant change occurred in the plasma levels of 2-AG in all the patients' groups. Moreover, circulating AEA levels were significantly and inversely correlated with plasma
leptin concentrations in both healthy controls and anorexic women. These findings show for the first time a derangement in the production of the endogenous
cannabinoid AEA in
drug-free symptomatic women with AN or with BED. Although the pathophysiological significance of this alteration awaits further studies to be clarified, it suggests a possible involvement of AEA in the mediation of the rewarding aspects of the aberrant eating behaviors occurring in AN and BED.