I. Juranek et V. Rekalov, Oxygenation of arachidonic acid under hypoxic conditions: some methodological aspects and possible biological relevance, BIOLOGIA, 55, 2000, pp. 49-53
Hypoxia has been shown to alter the arachidonic acid cascade in various tis
sues. Once released, arachidonic acid is immediately metabolized through li
poxygenase (LOX) and/or cyclooxygenase (COX) pathways. LOX incorporates one
molecule of oxygen at various carbon atoms of arachidonic acid, yeilding r
espective hydroperoxy-eicosatetraenoic acids, while COX inserts two molecul
es of oxygen into the fatty acid substrate, producing prostaglandin Ga Thus
, molecular oxygen, as the second substrate of the LOX- and COX-mediated ar
achidonate oxygenation, is required ai the first step of the arachidonic ac
id cascade. Previously, LOXs and COXs of mammalian origin have been broadly
studied wish regard to their fatty acid substrate specificity, and recentl
y, their affinities to molecular. oxygen were evaluated. Data oi the oxygen
dependency of these enzymes may help to understand their functions and an
involvement of the respective arachidonic acid-derived metabolites in cellu
lar biology. That may elucidate mechanisms of hypoxia-induced alterations o
f tissue functions mediated hy various eicosanoids. Findings about the affi
nities of the arachidonate oxygenases for molecular oxygen together with th
e knowledge of oxygen concentration in the tissue are used as basic informa
tion for the in vivo implication of eicosanoid synthesis under hypoxic cond
itions.