Autacoids

AUTACOID     

This term is derived from Greek:

autos—self, akos—healing substance or remedy.

These are diverse substances produced by a wide variety of cells in the body, having intense biological activity, but generally act locally (e.g. within inflammatory pockets) at the site of synthesis and release.

They have also been called ‘local hormones’. However, they differ from ‘hormones’ in two important ways—hormones are produced by specific cells, and are transported through circulation to act on distant target tissues.

Autacoids are involved in a number of physiological and pathological processes (especially reaction to injury and immunological insult) and even serve as transmitters or modulators in the nervous system, but their role at many sites is not precisely known. A number of useful drugs act by modifying their action or metabolism. The classical autacoids are—

Amine autacoids Histamine, 5Hydroxytryptamine (Serotonin)

Lipid derived autacoids Prostaglandins, Leukotrienes, Platelet activating factor

Peptide autacoids Plasma kinins (Bradykinin, Kallidin), Angiotensin

In addition, cytokines (interleukins, TNFα, GMCSF etc.) and several peptides like gastrin, somatostatin, vasoactive intestinal peptide and many others may be considered as autacoids.