Λεξικό .. Arachidonic acid

A polyunsaturated essential fatly acid with essential 20 carbon fatty acid with four double bonds [CH3 (CH2 )4  (CHE:CH:CH2 )4  (CH2 )2  COOH]. It is a constituent of lecithin and a biosynthetic source of some  prostaglandins. Arachidonic acid is released from a variety of cells upon activation and this may be oxygenated by either cyclooxygenase or lipoxygenase pathways. Oxidation of arachidonic acid by the cyclooxygenase pathway results in the formation of endoperoxides e.g. PgD2  and PgG2.

Further oxidation results in the formation of prostaglandins, such as PgE2  and PgF2a; thromboxanes, such as TxB2  and TxA2, and prostacyclins, such as PgI2. Arachidonate metabolism by the lipoxygenase eicosotetranoic acids (HETEs) can subsequently be converted to leukotrienes (See Leukotrienes).