Serum leptin levels in women with anorexia nervosa.

Abstract

Leptin is a protein encoded by the ob gene that is expressed in adipocytes and regulates eating behavior via central neuroendocrine mechanisms. Serum leptin levels have been shown to correlate with weight and percent body fat in normal and obese individuals; however, it is not known whether the regulation of leptin is normal below a critical threshold of body fat in chronic undernutrition. We investigated serum leptin levels in 22 women, aged 23 +/- 4 yr, with anorexia nervosa. Duration of disease, weight, BMI, percent body fat, and serum leptin levels were determined for each patient. Nutritional status was assessed further by caloric intake and measurement of insulin and insulin-like growth factor I (IGF-I) levels. Twenty-three healthy women, aged 23 +/- 4 yr, taking no medications, with normal menstrual function and body mass index (BMI) between 20-26 kg/m2 (mean, 23.7 +/- 1.7 kg/m2), served as a control population for comparison of leptin levels. Subjects with anorexia nervosa were low weight (BMI, 16.3 +/- 1.6 kg/m2; normal, 20-26 kg/m2) and exhibited a striking reduction in percent body fat (7 +/- 2%; normal, 20-30%). The mean serum leptin level was significantly decreased in subjects with anorexia nervosa compared with that in age- and sex-matched controls of normal body weight (5.6 +/- 3.7 vs. 19.1 +/- 8.1 ng/mL; P < 0.0001). Serum leptin levels were correlated highly with weight, as expressed either BMI (r = 0.66; P = 0.002) or percent ideal body weight (r = 0.68; P = 0.0005), body fat (r = 0.70; P = 0.0003), and IGF-I (r = 0.64; P = 0.001), but not with caloric intake or serum levels of estradiol or insulin in subjects with anorexia nervosa. The correlation between leptin and body fat was linear, with progressively lower, but detectable, leptin levels measured even in patients with less than 5% body fat, but was not significant when the effects of weight were taken into account. In contrast, the correlation between leptin and IGF-I remained significant when the effects of weight, body fat, and caloric intake were taken into account. In normal controls, leptin correlated with BMI (r = 0.55; P = 0.007) and IGF-I (r = 0.44; P < 0.05), but not with fat mass. These data demonstrate that serum leptin levels are reduced in association with low weight and percent body fat in subjects with anorexia nervosa compared to normal controls. Leptin levels correlate highly with weight, percent body fat, and IGF-I in subjects with anorexia nervosa, suggesting that the physiological regulation of leptin is maintained in relation to nutritional status even at an extreme of low weight and body fat.

Serum lipid and leptin concentrations in hypopituitary patients with growth hormone deficiency

“…Control subjects had leptin concentraLeptin and growth hormone de®ciency N Ozbey et al tions similar to those previously reported in healthy controls. 5,33,38 Our results might indicate increased production of leptin by per unit fat mass in GH de®ciency similar to the reported increase in ob messenger RNA content of adipocytes in obese humans. 5 Previous studies showed different results regarding leptin concentrations in GH de®ciency.…”

Clinical Implication of Leptin, the Obese Gene Product.

“…Furthermore, plasma leptin concentrations are significantly lower in patients with anorexia nervosa relative to those in healthy subjects (7). All of these findings are consistent with the notion that leptin reflects the total body fat content, thereby, suggesting that leptin may serve as a useful chemical marker of adiposity.…”

Adiposity, plasma leptin concentration and reproductive function in active and sedentary females

“…13,14 The relationship between adiposity and plasma leptin concentration seems to be independent of the level of exercise (our data, 13,15,16 ) and is true in extremes of nutritional status such as anorexia nervosa. 17 Furthermore, hormones other than leptin also respond to energy de®cit. For example, insulin decreases and cortisol increases in response to fasting, and both of these hormones are thought to regulate leptin expression/secretion.…”