Background. Serum leptin levels and resting energy expenditure are significantly decreased in patients with anorexia nervosa compared to healthy subjects. Partial realimentation of patients with anorexia nervosa increases both these parameteres. However, there so far are no data concerning the relationship of serum leptin levels and resting energy expenditure in patients with anorexia nervosa. The aim of our study was to follow the relationship of serum leptin levels and resting energy expenditure in patients with anorexia nervosa before and after refeeding. Methods and Results. It was found that serum leptin levels in patients with anorexia nervosa both before and after partial realimentation were significantly lower compared to healthy subjects (0.86 ± 0.9 ng . ml -1 and 1.77 ± 1.9 ng . ml -1 vs 6.85 ± 3.0 ng . ml -1 , p < 0.05). The total resting energy expenditure in patients with anorexia nervosa both before and after realimentation were significantly lower than in the control group (4973 ± 979 and 5263 ± 899 vs 6401 ± 827 kJ/day, p < 0.05). When expressed per body weight the resting energy expenditure in patients with anorexia nervosa was significantly higher in comparison with the control group (122.3 ± 20.6 and 121.5 ± 14.2 vs 104.2 ± 14.6 kJ/day, p < 0.05). The differences in resting energy expenditure in patients with anorexia nervosa before and after refeeding did not reach statistical significance. The body mass and the body fat content increased significantly after realimentation index (14.5 ± 1.4 vs 15.6 ± 1.5 kg . (m 2 ) -1 and 14.9 ± 3.4 vs 16.6 ± 3.7, p < 0.05) but remained still bellow of those of control group (BMI 22.3 ± 2.7, body fat content 26.9 ± 4.2). Conclusions. Our study confirmed the reduced serum leptin levels and the total resting energy expenditure in patients with anorexia nervosa compared to healthy age-matched subjects. No statistically significant relationships were found between serum leptin levels and resting energy expenditure either in healthy subjects or in patients with anorexia nervosa before or after partial realimentation respectively.

        Key words: leptin, anorexia nervosa, resting energy expenditure, realimentation.