Circulating monocytes are not the source of elevations in plasma IL-6 and TNF-alpha levels after prolonged running.
The present study was undertaken to examine the effect of prolonged running on monocyte intracellular cytokine production and plasma cytokine concentration. Blood samples were collected 1 h before, immediately after, 2 h after, and 24 h after a competitive marathon run. There was no change in the number of cells spontaneously producing tumor necrosis factor (TNF)-alpha; however, there was a decrease in the number of cells producing interleukin (IL)-1alpha and IL-6 (P < 0.01) postexercise. In contrast, there was an increase in the number of monocytes that responded to lipopolysaccharide stimulation by producing IL-1alpha, TNF-alpha, and IL-6 (P < 0.01) immediately and 2 h postexercise; however, these cells contained less cytokine (P < 0.05). Plasma IL-6, TNF-alpha, epinephrine, norepinephrine, and cortisol concentrations were markedly increased (P < 0.01) postexercise. These data demonstrate that circulating monocytes are not the source of elevated levels of plasma IL-6 and TNF-alpha after prolonged running. In addition, it is likely that stress hormones result in a decrease in the amount of cytokine produced by LPS-stimulated cells postexercise.
Exercise Physiology and Metabolism Laboratory, Department of Physiology, University of Melbourne, Parkville 3052, Victoria, Australia.
R L
RL
Starkie
J
J
Rolland
D J
DJ
Angus
M J
MJ
Anderson
M A
MA
Febbraio
D004837:Epinephrine / Q000097:blood; D005434:Flow Cytometry; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007375:Interleukin-1 / Q000097:blood; D015850:Interleukin-6 / Q000097:blood*; D007958:Leukocyte Count; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D009638:Norepinephrine / Q000097:blood; D010807:Physical Endurance / Q000276:immunology*; D012420:Running / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine