title: Serum leptin levels are inversely correlated with omental gene expression of adiponectin and markedly decreased after gastric bypass surgery.
abstract: BACKGROUND
  Adipose tissue is the most abundant endocrine tissue in the body, producing leptin, a hormone important in regulating hunger, and adiponectin, a hormone involved in insulin sensitivity and inflammation. This study aimed to assess the impact of gastric bypass surgery (GBS) on leptin levels and its relation to the adipose tissue expression of adiponectin.
  
  
  METHODS
  Omental and subcutaneous adipose tissue and serum were obtained from 40 obese patients undergoing GBS, from 13 patients 1 year or more after GBS, and from 16 non-obese individuals with a body mass index of 20 to 29 kg/m(2). Adiponectin gene expression was measured by quantitative real-time polymerase chain reaction, and the gene expression was normalized for the GAPDH gene. Serum leptin and adiponectin were measured by a high-sensitivity enzymatic assay.
  
  
  RESULTS
  Leptin levels were significantly lower in the post-GBS patients (19.8 ± 6.7) than in the pre-GBS patients (59.0 ± 5.1; P = 0.0001), and similar to those in the non-obese control subjects (18.2 ± 4; P = 0.8). Univariate analysis showed an inverse correlation between serum leptin levels and omental adiponectin gene expression (r = -0.32; P = 0.01).
  
  
  CONCLUSIONS
  Gastric bypass surgery results in resolution of the leptin resistance status that characterizes obese subjects. The study also demonstrated a significant correlation between leptin and adiponectin. This correlation provides preliminary evidence for studying a potential adiponectin-leptin cross-talking that may represent one of the physiologic pathways responsible for the regulation of food intake in humans.
authors.affiliation: Department of Surgery, Duke University, 407 Crutchfield Street, Durham, NC 27704, USA.
authors.forename: Jiegen
authors.initials: J
authors.lastname: Chen
authors.forename: Zehra
authors.initials: Z
authors.lastname: Pamuklar
authors.forename: Anna
authors.initials: A
authors.lastname: Spagnoli
authors.forename: Alfonso
authors.initials: A
authors.lastname: Torquati
mesh_terms: D052242:Adiponectin / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D015331:Cohort Studies; D005260:Female; D015390:Gastric Bypass; D006801:Humans; D050152:Intra-Abdominal Fat / Q000378:metabolism*; D020738:Leptin / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000235:genetics / Q000601:surgery*; D009852:Omentum / Q000378:metabolism*; D011184:Postoperative Period
chemical_list: D052242:Adiponectin; D020738:Leptin