Leptin, the product of the ob-gene, is specifically released by adipocytes. In 
addition to its metabolic function it seems to affect the feedback-mechanisms of 
the hypothalamic-pituitary-gonadal-axis. We studied 13 female juvenile elite 
gymnasts with anorexia athletica (AA) and 9 female patients with 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 
microg/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 microg/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 gymnasts 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 
microg/L; AA: 24.4 +/- 13.5 microg/L). A delay in menarche and a retarded bone 
maturation occurred in AA. Our results clearly show that leptin levels are low 
in restrained eaters. Leptin levels represent the fat stores in the body and 
play a permissive role for female pubertal development. 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 and AA are overlapping groups and AA can 
lead to the development of AN.