Cytokines which play an important role in the metabolic response to injury include:

a. Tumor necrosis factor—a (TNF)

b. Interleukin-1 (IL-1)

c. Interleukin-6 (IL-6)

d. Interferon-g

TNF or cachetin is considered the primary mediator of the systemic effects of endotoxin, producing anorexia, fever, tachypnea, and tachycardia at low doses and hypotension, organ failure, and death at higher doses. TNF is produced primarily by macrophages, but lymphocytes, Kupffer cells, and a number of other cell types have been identified as sources of TNF. IL-1, like TNF, has a variety of pro-inflammatory activities. IL-6 is now recognized as a primary mediator of altered hepatic protein synthesis known as acute-phase protein synthetic response. Glucocorticoid hormones augment the cytokine effects on acute phase protein synthesis. Interferons are a family of proteins which are readily identified for their ability to inhibit viral replication in infected sells. IFN-g has the ability to upregulate the number of TNF receptors on various cell types.