Leptin in functional hypothalamic amenorrhoea.
BACKGROUND: Leptin, body weight, body mass index (BMI) and other hormones in women with functional hypothalamic amenorrhoea (FHA) were investigated and the hypothesis proposed that energy imbalance is the predominant mechanism for leptin reduction in patients with FHA. METHODS: Eighty-eight women with FHA and 65 age- and weight-matched controls were divided into homogeneous groups on the basis of their BMI: women with different degrees of underweight (BMI 15-16, 17-18 kg/m(2)) and of normal weight (BMI 19-21, 22-24 kg/m(2)). Hormone and carrier protein assays were measured in all groups. RESULTS: In each BMI group of patients with FHA, gononadotrophins, prolactin, insulin, free tri-iodothyronine and leptin levels were significantly lower than those of the respective controls, whereas cortisol and insulin-like growth factor (IGF)-binding protein-1 (IGFBP-1) were higher. We found significant linear positive correlations between leptin and body weight, BMI, LH, peptide-C, insulin, IGF-1 values and negative correlations with cortisol and IGFBP-1. CONCLUSIONS: Leptin values in women with FHA are significantly lower than controls, even in the group of patients having normal body weight and BMI. Leptin profile is different between patients with FHA and controls: it is suggested that energy balance can interfere with the ratio of body weight/leptin and BMI/leptin in FHA.