LEPTIN IN ANOREXIA-NERVOSA

Serum leptin levels are low in untreated anorexia nervosa, but studies of the exact relationship between leptin and body weight and the impa ct of refeeding in anorectics are limited. Therefore, we studied serum leptin, insulin-like growth factor I, and other endocrine parameters in female anorectics before and after gaining weight and in female nor mal body weight controls. Leptin levels in untreated anorectics were s ignificantly lower than those in normal body weight controls (3.6 +/- 1.6 vs. 12.0 +/- 6.9 ng/mL; P < 0.001), and they uncoupled from body w eight in a nonlinear relationship, suggesting a threshold effect at lo west body weights. Leptin increased significantly with refeeding (5.6 +/- 3.8 ng/mL; P < 0.01). The significant linear correlations of lepti n with body mass index in the anorectics after weight gain and In norm al body weight controls (r = 0.69; P < 0.001 and r = 0.76; P < 0.001, respectively) are consistent with a normal physiological increase in l eptin with weight gain. Leptin and insulinlike growth factor I were hi ghly correlated, even after controlling for body weight (r = 0.63; P = 0.001) during starvation, but were no longer significantly correlated after body weight gain in the anorectics or the normal body weight co ntrols. Further studies are necessary to elucidate the relationship of leptin to neuroendrocrine abnormalities seen in starvation and to det ermine a possible contribution of leptin to difficulties with weight r estoration in anorexia nervosa.