title: Relationships between serum soluble leptin receptor level and serum leptin and adiponectin levels, insulin resistance index, lipid profile, and leptin receptor gene polymorphisms in the Japanese population.
abstract: Leptin plays an important role in the regulation of body weight and is known to circulate in both free and bound forms. One of the leptin receptor isoforms exists in a circulating soluble form that can bind leptin. Clinical studies have shown that soluble leptin receptor (sOB-R) levels are lower in obese individuals. In the present study, we measured the serum sOB-R level in 419 healthy Japanese subjects (198 men and 221 women, aged 30 to 65 years, body mass index [BMI] 21.7 +/- 2.6 [SD] kg/m2) and in 150 type 2 diabetic patients (96 men and 54 women, BMI 24.3 +/- 3.8 kg/m2). We investigated the relationships between serum sOB-R level and BMI, blood pressure, homeostasis model assessment-insulin resistance index (HOMA-IR), serum leptin and adiponectin levels, lipid profile, and leptin receptor (LEPR) gene Lys109Arg and Gln223Arg polymorphisms. Serum leptin and sOB-R levels were measured by radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA), respectively. The serum sOB-R level in men was significantly higher than that in women. The serum sOB-R level was negatively correlated with BMI, fasting insulin, HOMA-IR, and serum leptin level and positively correlated with high-density lipoprotein (HDL)-cholesterol and serum adiponectin levels. The correlations between serum sOB-R level and fasting insulin, HOMA-IR, serum leptin, adiponectin, and HDL-cholesterol levels were significant even after adjustment for age, sex, and BMI in healthy subjects. There was no association between serum sOB-R level and the LEPR polymorphisms examined. These findings suggest that the serum sOB-R level is negatively correlated with HOMA-IR and serum leptin level and positively correlated with HDL-cholesterol level and serum adiponectin level, independent of age, sex, and BMI, in the Japanese population.
authors.affiliation: Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Ogawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hirose
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Kanako
authors.initials: K
authors.lastname: Nishikai
authors.forename: Kiichi
authors.initials: K
authors.lastname: Miyashita
authors.forename: Haruo
authors.initials: H
authors.lastname: Nakamura
authors.forename: Ikuo
authors.initials: I
authors.lastname: Saito
authors.forename: Takao
authors.initials: T
authors.lastname: Saruta
mesh_terms: D052242:Adiponectin; D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D015342:DNA Probes; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D036341:Intercellular Signaling Peptides and Proteins; D007564:Japan; D020738:Leptin / Q000097:blood*; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic / Q000235:genetics*; D011153:Population; D011506:Proteins / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000097:blood* / Q000235:genetics*; D054411:Receptors, Leptin; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D052242:Adiponectin; D015342:DNA Probes; D036341:Intercellular Signaling Peptides and Proteins; C515448:LEPR protein, human; D020738:Leptin; D008055:Lipids; D011506:Proteins; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin