TY - JOUR
T1 - Leptin in anorexia nervosa and bulimia nervosa
T2 - Importance of assay technique and method of interpretation
AU - Frederich, Robert
AU - Hu, Shousheng
AU - Raymond, Nancy C
AU - Pomeroy, Claire
N1 - Funding Information:
Supported in part by grant RO1 DK50556-04 from the National Institute of Diabetes, Digestive and Kidney Diseases and Veterans Administration Career Development Award 596522803585003.
PY - 2002
Y1 - 2002
N2 - Studies of the role of leptin in patients with anorexia nervosa and bulimia nervosa have conflicted in their data and interpretation. Such differences may be a result of the assay methods used or the way results are compared with those from normal controls. To investigate these possibilities, we analyzed serum leptin levels in anorexic, bulimic, obese, and control individuals, thereby spanning the full range of human body weights, using three frequently employed commercial kits. Kits from Linco (St Louis, MO) and DSL (Webster, TX) employ a radioimmunoassay method, and the R&D Systems kit (Minneapolis, MN) uses an enzyme-linked immunosorbent assay. We found that the three kits provide results that are highly linearly correlated with each other and remarkably linearly related to percent ideal body weight (%IBW) over more than three orders of magnitude (Linco, r = 0.90; R&D, r = 0.87; DSL, r= 0.86). For very low leptin levels, the more sensitive kits from R&D and Linco appeared to give more reliable results. Measurement method does not appear to explain the literature conflicts. We found that patients with anorexia nervosa have serum leptin values that lie above the line extrapolated from the %IBW/leptin curve generated from analysis of all nonanorexic patients. Therefore, in anorexia nervosa, inappropriately high leptin levels for %IBW may contribute to a blunted physiologic response to underweight and consequent resistance to dietary treatment. By contrast, most bulimic patients have leptin levels significantly below those predicted from the same %IBW/leptin curve. The relative leptin deficiency in bulimic subjects may contribute to food-craving behavior. We propose that using the %IBW/leptin curve can facilitate identification of true pathophysiologic abnormalities in eating-disordered individuals and provide a basis for the design of therapeutic interventions or monitoring of response to treatment.
AB - Studies of the role of leptin in patients with anorexia nervosa and bulimia nervosa have conflicted in their data and interpretation. Such differences may be a result of the assay methods used or the way results are compared with those from normal controls. To investigate these possibilities, we analyzed serum leptin levels in anorexic, bulimic, obese, and control individuals, thereby spanning the full range of human body weights, using three frequently employed commercial kits. Kits from Linco (St Louis, MO) and DSL (Webster, TX) employ a radioimmunoassay method, and the R&D Systems kit (Minneapolis, MN) uses an enzyme-linked immunosorbent assay. We found that the three kits provide results that are highly linearly correlated with each other and remarkably linearly related to percent ideal body weight (%IBW) over more than three orders of magnitude (Linco, r = 0.90; R&D, r = 0.87; DSL, r= 0.86). For very low leptin levels, the more sensitive kits from R&D and Linco appeared to give more reliable results. Measurement method does not appear to explain the literature conflicts. We found that patients with anorexia nervosa have serum leptin values that lie above the line extrapolated from the %IBW/leptin curve generated from analysis of all nonanorexic patients. Therefore, in anorexia nervosa, inappropriately high leptin levels for %IBW may contribute to a blunted physiologic response to underweight and consequent resistance to dietary treatment. By contrast, most bulimic patients have leptin levels significantly below those predicted from the same %IBW/leptin curve. The relative leptin deficiency in bulimic subjects may contribute to food-craving behavior. We propose that using the %IBW/leptin curve can facilitate identification of true pathophysiologic abnormalities in eating-disordered individuals and provide a basis for the design of therapeutic interventions or monitoring of response to treatment.
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U2 - 10.1067/mlc.2002.121014
DO - 10.1067/mlc.2002.121014
M3 - Article
C2 - 11919545
AN - SCOPUS:0036009341
SN - 0022-2143
VL - 139
SP - 72
EP - 79
JO - Journal of Laboratory and Clinical Medicine
JF - Journal of Laboratory and Clinical Medicine
IS - 2
ER -