Acute hyperinsulinaemia and hyperlipidaemia modify circulating adiponectin and its oligomers.
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.
Bobbert
Thomas
T
Department of Endocrinology, Diabetes and Nutrition, Charité-Universitymedicine Berlin, Berlin, Germany.
Weicht
Jessica
J
Mai
Knut
K
Möhlig
Matthias
M
Pfeiffer
Andreas F H
AF
Spranger
Joachim
J
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
D052242:Adiponectin; D005230:Fatty Acids, Nonesterified; D008055:Lipids; D014280:Triglycerides