The role of leptin and cortisol in hyperactivity in patients with acute and weight-recovered anorexia nervosa.

INTRODUCTION: In food-restricted rats, leptin as well as corticotropin releasing factor attenuate semistarvation-induced hyperactivity (SIH). Results from studies in patients with anorexia nervosa (AN) showed an association between excessive physical activity (PA) and leptin. One recent report suggests a role for cortisol in PA. In this study, we assessed the relationships between PA and both, cortisol and leptin levels at the same time in patients with acute anorexia nervosa (acAN) in comparison to recovered patients (recAN).

METHODS: Plasma leptin, plasma cortisol, body mass index (BMI), and expert-ratings of qualities of PA were assessed in 36 acAN patients, 27 recAN patients and 44 healthy control woman (HCW). Regression analyses were used to predict PA using BMI, leptin and cortisol levels as predictor variables.

RESULTS: Leptin levels but not cortisol significantly contributed to the prediction of PA in acAN. In recAN PA was not elevated and not related to endocrine parameters but correlated positively with core eating disorder symptoms.

CONCLUSIONS: Our work lends support to the proposed inverse association between peripheral leptin levels and excessive physical activity in AN. This relationship is specific to the state of semistarvation. The role of additional mediators remains to be clarified.