The Tumor necrosis factor reference article from the English Wikipedia on 24-Jul-2004 (provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

Tumor necrosis factor

medicine, tumor necrosis factor alpha (TNFα, cachexin or cachectin) is an important cytokine involved in systemic inflammation and the acute phase response.

Table of contents

1 Structure 2 Physiology 3 Pharmacology 4 See also 5 External link

Structure

TNFα is a member of a group of other cytokines that all stimulate the acute phase reaction. It is a 185 amino acid glycoprotein peptide hormone, cleaved from a 212 amino acid-long propeptide. Some cells secrete shorter or longer isoforms. Genetically it links to chromosome 7p21.

Physiology

TNFα is released by white blood cells, endothelium and several other tissues in the course of damage, e.g. by infection. Its release is stimulated by several other mediators, such as interleukin 1 and bacterial endotoxin. It has a number of actions on various organ systems, generally together with interleukins 1 and 6:

• On the hypothalamus:
  • Stimulating of the hypothalamic-pituitary-adrenal axis by stimulating the release of corticotropin releasing hormone (CRH).
  • Suppressing appetite (hence its name "cachexin" - cachexia is severe weight loss in illness.
  • Fever.
• On the liver: stimulating the acute phase response, leading to an increase in C-reactive protein and a number of other mediators.
• On other tissues: increasing insulin resistance.

Pharmacology

Inhibition of TNFα with a monoclonal antibody or a circulating receptor is used in modern treatment of various autoimmune disorders, most notably rheumatoid arthritis (infliximab/Remicade® and etanercept/Enbrel®).

See also

• Interleukin
• Cytokine

External link

• TNF page.

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