Year: 2010
Type: article
Abstract: BACKGROUNDInterleukin-6 (IL-6) belongs to a family of cytokines, which are proteins secreted from various cell types in response to stimuli 1 .IL-6 is typically reported as a pro-inflammatory 2 cytokine, but it has also been seen to partially mediate an antiinflammatory response 3 .In metabolism, IL-6 increases the availability of blood glucose and free fatty acids by increasing lipolysis in adipose tissue and glycogenolyis in the liver 4 .It is believed that IL-6 expression and release from contracting skeletal muscle may play a vital role in systemic metabolism by its regulation of substrate availability and use 5 (Figure 1).Such coordination has important implications for defining how physical activity protects against, and inactivity promotes, the development of chronic metabolic disorders.The exercise-induced elevation of plasma IL-6 has created an interest for its role in initiating biochemical signaling pathways in skeletal muscle, regulating metabolism in healthy individuals, as well as the potential for altered IL-6 function in states of metabolic disease such as type 2 diabetes and obesity 6 .However, IL-6's influence on specific aspects of energy metabolism remains a topic of considerable debate 6 .Because IL-6 is produced in and released from skeletal muscle during exercise, some scientists have termed it a "myokine."As a result, skeletal muscle is now seen in a new role: an endocrine organ that produces and secretes myokines in response to exercise 6 .Exercise intensity is known to be an important factor in plasma IL-6 concentrations 2 .Higher intensity levels elicit higher concentrations of IL-6, but the specific mechanisms and reasons for this finding remain a topic of debate.Peak levels of IL-6 are reached at the end of the exercise, or shortly thereafter 7 .Although several studies have evaluated the IL-6 response to endurance exercise 8, 9 , the literature lacks a thorough study of how repeated bouts of high-intensity exercise affect IL-6.
Author: Carolyn E. Moore
Language: English
Subfield: Physiology (medical)
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W95394548