Use of a continuous assay of oxygen consumption to evaluate the pharmacology of 5-lipoxygenase inhibitors.
A variety of assay systems have been utilized to evaluate the inhibition of the key enzyme in leukotriene (LT) biosynthesis, 5-lipoxygenase (5-LO). We have developed an assay utilizing a cytosolic preparation of 5-LO from rat basophilic leukemia (RBL-1) cells. Enzyme activity was monitored by continuous measurement of oxygen consumption. High performance liquid chromatography (HPLC) analysis of products showed exclusive generation of 5-LO products. The assay proved useful for the evaluation of a variety of chemical classes of lipoxygenase inhibitors and clearly differentiated those compounds which extended the lag phase (e.g. A-64077) as opposed to the propagation phase of the enzyme activity (e.g. SK & F 105561). The data generated were in reasonable agreement with results from the assay of isolated human monocyte 5-LO and, with the exception of compounds which appear to have a significant effect on 5-LO translocation (e.g. MK-886 and Wy-49 232), inhibition of LT production by intact monocytes. This assay system proved to be a convenient and informative method to analyze inhibition of 5-LO activity.
Breton
J
J
Department of Respiratory/Inflammation Pharmacology, SmithKline Beecham Pharmaceuticals, King of Prussia, PA 19406-0939.
Keller
P
P
Chabot-Fletcher
M
M
Hillegass
L
L
DeWolf
W
W
Griswold
D
D
D015117:5,8,11,14-Eicosatetraynoic Acid / Q000494:pharmacology; D000818:Animals; D004353:Drug Evaluation, Preclinical / Q000379:methods; D006801:Humans; D006918:Hydroxyurea / Q000031:analogs & derivatives / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D007975:Leukotriene B4 / Q000096:biosynthesis; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology*; D009000:Monocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects*; D051381:Rats; D014407:Tumor Cells, Cultured / Q000201:enzymology
D007093:Imidazoles; D016859:Lipoxygenase Inhibitors; D015117:5,8,11,14-Eicosatetraynoic Acid; C067915:SK&F 105561; D007975:Leukotriene B4; C063449:zileuton; D006918:Hydroxyurea