title: Acute hyperinsulinaemia and hyperlipidaemia modify circulating adiponectin and its oligomers.
abstract: OBJECTIVE
  Obesity and insulin resistance are associated with low adiponectin levels, although adiponectin is exclusively expressed in white adipose tissue. The mechanism beyond that paradox is not entirely clear, although insulin itself may reduce circulating adiponectin levels. However, obesity is also associated with hyperlipidaemia and the effects of free fatty acids (FFAs) and triglycerides (TG) on circulating adiponectin levels have not yet been investigated.
  
  
  METHODS
  We analysed the effect of an acute and euglycaemic elevation of insulin on adiponectin oligomers in 23 healthy individuals. In a subgroup including 11 healthy men, FFAs and TG were acutely elevated by infusion of heparin/lipids over 120 min. Again the effect on circulating adiponectin and its oligomers was investigated. Adiponectin was determined by ELISA, oligomers were detected by nondenaturating Western blot.
  
  
  RESULTS
  Acute hyperinsulinaemia resulted in a significant reduction of total adiponectin to 7.74 +/- 0.98 microg/ml (P = 0.004). High molecular weight (HMW) adiponectin did not change (0.80 +/- 0.12 to 0.81 +/- 0.14 microg/ml; P = 0.887), whereas MMW adiponectin decreased from 4.30 +/- 0.51 to 3.78 +/- 0.48 microg/ml (P = 0.005) and LMW adiponectin from 3.63 +/- 0.42 to 3.15 +/- 0.46 microg/ml (P = 0.048). Interestingly, heparin/lipid infusion also reduced circulating adiponectin levels (P = 0.001), which was primarily the result of reduced MMW adiponectin (P = 0.004), whereas LMW and HMW were not significantly affected.
  
  
  CONCLUSIONS
  The presented data suggest that both, hyperinsulinaemia and hyperlipidaemia, may contribute to low adiponectin levels in states of obesity.
authors.affiliation: Department of Endocrinology, Diabetes and Nutrition, Charité-Universitymedicine Berlin, Berlin, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bobbert
authors.forename: Jessica
authors.initials: J
authors.lastname: Weicht
authors.forename: Knut
authors.initials: K
authors.lastname: Mai
authors.forename: Matthias
authors.initials: M
authors.lastname: Möhlig
authors.forename: Andreas F H
authors.initials: AF
authors.lastname: Pfeiffer
authors.forename: Joachim
authors.initials: J
authors.lastname: Spranger
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000328:Adult; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood*; D006949:Hyperlipidemias / Q000097:blood*; D008055:Lipids / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D009765:Obesity / Q000097:blood; D055503:Protein Multimerization; D014280:Triglycerides / Q000097:blood
chemical_list: D052242:Adiponectin; D005230:Fatty Acids, Nonesterified; D008055:Lipids; D014280:Triglycerides