Malnourished patients with AN experience a myriad of endocrine disturbances including amenorrhea which is characterized by a return to prepubertal gonadotropin secretory patterns and estradiol levels. We recently found that 68% of nutritionally rehabilitated patients with AN resumed normal menstrual function within 1 year. There were no significant differences in weight,% body fat or BMI between those who resumed menses and those who remained amennorheic. The amennorheic group did have lower estradiol and gonadotropin levels. Serum leptin, the product of the adipocyte specific ob gene, is highly correlated with measures of body fat mass and has profound effects on reproductive function in the ob/ob mouse. Leptin deficient mice remain prepubertal with puberty and ovulation induced by leptin injections.

We studied leptin levels in nutritionally rehabiliated women with restrictive AN, 12 who regained menses (mean age 17.0±2.9yrs) and 12 who remained amennorheic (16.8±5.5). Leptin was assayed with a commercial kit (Linco Research, Inc). Results were analyzed with Student's t-test. 1 patient was eliminated as an outlier with a leptin value > 3 s.d. from the mean.

Results: Women who regained menses had significantly increased leptin levels than those who remained amennorheic at 1 year follow-up(8.53±3.04 ng/ml versus 5.76±2.17 ng/ml p < 0.05). There was no difference in body weight (104.9±8.7 lbs versus 108.8.±12.1),% ideal body weight (89.3±3.2 versus 88.2±5.3) or% body fat (20.67±2.9 versus 20.15±3.9) between the 2 groups.

Conclusion: Serum leptin levels are higher in women with AN who regain their menses than those who remain amennorheic despite no difference in body fat. In this population there appears to be an association between reproductive function and leptin levels independent of gross measures of nutritional status.