title: Oral but not intravenous glucose acutely decreases circulating interleukin-6 concentrations in overweight individuals.
abstract: BACKGROUND
  Plasma interleukin-6 (IL-6) concentrations decrease acutely 1 h after ingestion of a glucose load or mixed meals and this may be mediated by an anti-inflammatory effect of insulin. The aim of the present study was to compare the effect of higher versus lower insulin levels on plasma IL-6 concentrations following oral compared with intravenous glucose administration in overweight/obese subjects.
  
  
  RESULTS
  Fifteen subjects (12 women and 3 men) with BMI >28 kg/m(2) were given an oral glucose load (75 g) followed a week later by an intravenous infusion of glucose aimed at matching plasma glucose concentrations during the oral glucose load. A week later, they drank a volume of water equivalent to the volume consumed with the oral glucose load. Plasma glucose, insulin, nonesterified fatty acids, and IL-6 concentrations and blood hematocrit were measured at 30 minute intervals for 2 h following each intervention. Plasma IL-6 decreased (13-20%) significantly (P = 0.009) at 30 min to 90 min following the oral glucose load and did not change significantly following the other two interventions. The incremental area under the curve for plasma IL-6 concentrations following oral intake of glucose was significantly lower compared with concentrations following intravenous glucose (P = 0.005) and water control (P = 0.02). Circulating insulin concentrations were significantly (P<0.001) and 2.8 fold higher following oral compared with intravenous glucose administration.
  
  
  CONCLUSIONS
  These data show that plasma IL-6 concentrations did not decrease during isoglycemic, intravenous glucose administration suggesting that the markedly higher circulating insulin levels and/or gut-related factors may mediate the acute decrease in plasma IL-6 after oral glucose intake in overweight/obese subjects.
  
  
  BACKGROUND
  Australian New Zealand Clinical Trials Registry ACTRN12612000491864.
authors.affiliation: Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand. PatrickManning@healthotago.co.nz
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Manning
authors.forename: Wayne H F
authors.initials: WH
authors.lastname: Sutherland
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Williams
authors.forename: Sylvia A
authors.initials: SA
authors.lastname: de Jong
authors.forename: Gavin P
authors.initials: GP
authors.lastname: Hendry
mesh_terms: D061605:Administration, Intravenous; D000284:Administration, Oral; D019540:Area Under Curve; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology*; D006400:Hematocrit; D006801:Humans; D007328:Insulin / Q000097:blood; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D050177:Overweight / Q000097:blood*
chemical_list: D005230:Fatty Acids, Nonesterified; D007328:Insulin; D015850:Interleukin-6; D005947:Glucose