beta-Adrenergic regulation of proinflammatory cytokines in humans.
OBJECTIVE
To investigate the effects of beta-adrenergic stimulation on IL-6 secretion in humans, and to determine the potential contribution to this response of adipocytes and peripheral blood cells (PBC).


METHODS
Experimental study in 8 human volunteers, and in vitro studies on murine adipocyte cell-line, 3T3.L1 and 3T3.F442A, and human PBC.


METHODS
Plasma IL-6 and TNFalpha responses to isoprenaline infusion. Cytokine secretion from differentiated adipocyte cell-lines and PBC in response to isoprenaline.


RESULTS
Plasma IL-6 levels increased ninefold (median) by 180 min (baseline median 0.51 [interquartile range 0.47-1.4] vs 180 mins 4.53 [2.58-5.69] pg ml(-1), P=0.01). One hour after infusion, IL-6 levels (2.9 [1.27-3.98]) were lower than at 180 min (P=0.05), but higher than baseline (P=0.01). TNFalpha levels were unchanged. Differentiated adipocytes incubated in isoprenaline (0-0.1 microM) released significantly increased amounts of IL-6 whereas no response was elicited from PBC.


CONCLUSIONS
The induction of IL-6 observed in vivo may be attributed to the beta-adrenergic stimulation of IL-6 release specifically from adipocytes, as opposed to circulating blood cells.
Mohamed-Ali
V
V
Department of Medicine, University College London Medical School, Whittington Hospital, UK. rmhauma@ucl.ac.uk
Bulmer
K
K
Clarke
D
D
Goodrick
S
S
Coppack
S W
SW
Pinkney
J H
JH
D016475:3T3 Cells; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism; D000318:Adrenergic beta-Agonists; D000328:Adult; D000818:Animals; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D007545:Isoproterenol; D007700:Kinetics; D008297:Male; D051379:Mice; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D000318:Adrenergic beta-Agonists; D015850:Interleukin-6; D011943:Receptors, Adrenergic, beta; D014409:Tumor Necrosis Factor-alpha; D007545:Isoproterenol