Proceedings of the Nutrition Society

Plenary Lecture

The metabolic role of IL-6 produced during exercise: is IL-6 an exercise factor?

B. K. Pedersena1a2 c1, A. Steensberga1a2, C. Fischera1a2, C. Kellera1a2, P. Kellera1a2, P. Plomgaarda1a2, E. Wolsk-Petersena1a2 and M. Febbraioa1

a1 The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, DK-2100, Copenhagen, Denmark

a2 Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, DK-2100, Copenhagen, Denmark

Abstract

For most of the last century, researchers have searched for a muscle contraction-induced factor that mediates some of the exercise effects in other tissues such as the liver and the adipose tissue. It has been called the ‘work stimulus’, the ‘work factor’ or the ‘exercise factor’. In the search for such a factor, a cytokine, IL-6, was found to be produced by contracting muscles and released into the blood. It has been demonstrated that IL-6 has many biological roles such as: (1) induction of lipolysis; (2) suppression of TNF production; (3) stimulation of cortisol production. The IL-6 gene is rapidly activated during exercise, and the activation of this gene is further enhanced when muscle glycogen content is low. In addition, carbohydrate supplementation during exercise has been shown to inhibit the release of IL-6 from contracting muscle. Thus, it is suggested that muscle-derived IL-6 fulfils the criteria of an exercise factor and that such classes of cytokines could be termed ‘myokines’.

Correspondence:

c1 *Corresponding author: Professor Bente Klarlund Pedersen, Fax: +45 35 45 76 44, Email: bkp@rh.dk