Hypoleptinaemia in patients with anorexia nervosa and in elite gymnasts with anorexia athletica

Leptin, the product of the ob-gene, is specifically released by adipocytes. In addition to its metabolic function it seems to affect the feedback-mech anisms of the hypothalamic-pituitary-gonadal-axis. We studied 13 female juv enile elite gymnasts with anorexia athletica (AA) and 9 female patients wit h anorexia nervosa (AN) regarding the relation between leptin, fat stores, and the reproductive hormone levels. Leptin levels in females with anorexia nervosa (Tanner stage B4 [median]; mean age: 17.8 +/- 1.7 years) were low (2.9 +/- 2.7 mu g/L), and were related to body mass index (BMI) (r = 0.71; p = 0.03) and percentage body fat mass (r = 0.78; p = 0.01). Leptin levels of the elite gymnasts were even more decreased (1.2 +/- 0.8 mu g/L) caused by the low amount of fat stores. Leptin correlated with BMI (r = 0.77; p = 0.004) and the percentage body fat mass (r = 0.6; p = 0.04). In elite gymna sts leptin levels correlated with CA showing an age-dependent increase (r = 0.59; p = 0.04). Oestradiol was secreted at a low level in both groups (AN : 25.6 +/- 17.4 mu g/L; AA: 24.4 +/- 13.5 mu g/L). A delay in menarche and a retarded bone maturation occurred in AA. Our results clearly show that le ptin levels are low in restrained eaters. Leptin levels represent the fat s tores in the body and play a permissive role for female pubertal developmen t. There is evidence that the mechanisms leading to a dysregulation of the reproductive-axis in patients with AN are comparable with those leading to delayed puberty in juvenile elite gymnasts with AA. This implies that AN an d AA are overlapping groups and AA can lead to the development of AN.