Hepatosplanchnic clearance of interleukin-6 in humans during exercise

Mark A. Febbraio, Peter Ott, Henning Bay Nielsen, Adam Steensberg, Charlotte Keller, Peter Krustrup, Niels H. Secher, Bente Klarlund Pedersen

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Abstract

The cytokine interleukin (IL)-6 can increase markedly in the circulation during exercise, but whether the liver is a source of this increase is unknown. The aim of this study was to measure IL-6 flux across the hepatosplanchnic tissues in humans. To elevate systemic concentrations of IL-6, six healthy male subjects performed 120 min of semirecumbent cycling, and blood samples were simultaneously obtained from a brachial artery and the hepatic vein before and during exercise for the analysis of IL-6. Hepatosplanchnic blood flow (HBF) was measured using the indocyanine green infusion technique. Net hepatosplanchnic IL-6 balance was calculated from these measures. HBF was 1.3 ± 0.1 l/min at rest and was not reduced throughout exercise, averaging 1.1 ± 0.2 l/min. Arterial plasma IL-6 markedly increased (P < 0.05) from 1.8 ± 0.6 ng/l at rest to 14.3 ± 3.2 ng/l after 120 min of exercise. The hepatosplanchnic viscera did not contribute to this increase, since there was a net hepatosplanchnic IL-6 uptake (0.8 ± 0.3 vs. 5.5 ± 1.9 ng/min, rest vs. 120 min; P < 0.05). These data demonstrate that the hepatosplanchnic viscera remove IL-6 from the circulation in humans. This removal may constitute a mechanism limiting the negative chronic metabolic action of chronically elevated circulating IL-6.

Original languageEnglish
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume285
Issue number2 48-2
Publication statusPublished - 1 Aug 2003
Externally publishedYes

Keywords

  • Blood flow
  • Cytokine
  • Liver
  • Metabolism
  • Skeletal muscle contraction

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