Comparison of the induction of cyclooxygenase and nitric oxide synthase by endotoxin in endothelial cells and macrophages.
Endotoxin causes the expression of inducible nitric oxide (NO) synthase and cyclooxygenase-2. We have compared the ability of endotoxin to increase the activities of these enzymes in bovine aortic endothelial cells and the macrophage cell line (J774.2). Endotoxin (1 microgram ml-1; for 24 h) caused a time-dependent increase in the accumulation of cyclooxygenase metabolites from endogenous arachidonic acid, in both cell types. Cyclooxygenase activity towards exogenous arachidonic acid (30 microM; for 15 min) was also increased in both cell types. Endothelial cells and macrophages also contained comparable amounts of cyclooxygenase-2 protein after incubation with endotoxin for 24 h which was prevented by pretreatment with cycloheximide (10 micrograms ml-1; 30 min prior to endotoxin). Endotoxin for 24 h caused a time-dependent increase in nitrite accumulation in macrophages, but not in endothelial cells. Thus, endotoxin increased cyclooxygenase activity and induced cyclooxygenase-2 protein in endothelial cells and macrophages. Endotoxin also increased NO synthase activity in macrophages, but not in endothelial cells.
Akarasereenont
P
P
William Harvey Research Institute, St. Bartholomew's Hospital Medical College, London, UK.
Mitchell
J A
JA
Bakhle
Y S
YS
Thiemermann
C
C
Vane
J R
JR
D000594:Amino Acid Oxidoreductases / Q000096:biosynthesis*; D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism; D015153:Blotting, Western; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D004731:Endotoxins / Q000494:pharmacology*; D004926:Escherichia coli; D007527:Isoenzymes / Q000096:biosynthesis* / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology*; D051379:Mice; D019001:Nitric Oxide Synthase; D009573:Nitrites / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000378:metabolism
D001095:Arachidonic Acids; D004731:Endotoxins; D007527:Isoenzymes; D009573:Nitrites; D003513:Cycloheximide; D019001:Nitric Oxide Synthase; D011451:Prostaglandin-Endoperoxide Synthases; D000594:Amino Acid Oxidoreductases