The effect of methotrexate on ex vivo lipoxygenase metabolism in neutrophils from patients with rheumatoid arthritis.

Hawkes, J S; Cleland, L G; Proudman, S M; James, M J · J Rheumatol · 1994

basic_science · Level V

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Abstract

To examine the effect of methotrexate (MTX) administered in vivo on the production of the 5-lipoxygenase (5-LO) metabolites of arachidonic acid by neutrophils from subjects with rheumatoid arthritis. Neutrophils were isolated from peripheral blood samples taken 12 h before and 12 h after the ingestion of an oral dose of MTX and stimulated in vitro by calcium ionophore A23187. Lipid extracts of cell suspensions were assayed for leukotriene B4 (LTB4), the all-trans isomers of LTB4, 20-hydroxy LTB4 and 5-hydroxyeicosatetraenoic acid by high pressure liquid chromatography. An increase in the production of all measured 5-LO metabolites was seen between the pre and postdose assessments. Our results do not support the putative inhibitory effect of MTX on 5-LO metabolism.

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