Do human platelets express COX-2?
The rate-limiting enzyme in prostaglandin (PG)- and thromboxane (TX)-synthesis is known as cyclooxygenase (COX). The COX-enzyme family consists of the classical COX-1 and the inducible COX-2-enzyme. To investigate whether platelets contain COX-2, we measured thiobarbituric acid reactive substances (TBARS) after either blocking COX-1 or COX-2 or adding compounds known to affect COX-expression. To stimulate platelets' different reagents such as collagen, thrombin and arachidonic acid (AA) were used. The inhibitors used in this study were acetylsalicylic acid (ASA), indomethacin and NS-398. Using the western-blot technique, we failed to detect COX-2 in platelets while COX-1 was detectable. We were not able to discover COX-2 in platelets using the methods we applied. As the amount of COX-2 in platelets might be below the detection limit of the methods used, the biological relevance COX-2 in platelets, if even existing at low amounts, remains to be established.
Reiter
R
R
Department of Nuclear Medicine, University of Vienna, Währinger Gürtel 19-20, A-1090 Vienna, Austria.
Resch
U
U
Sinzinger
H
H
D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000201:enzymology*; D015153:Blotting, Western; D019411:Clinical Laboratory Techniques; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D015539:Platelet Activation / Q000187:drug effects; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis / Q000378:metabolism
D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007527:Isoenzymes; D008565:Membrane Proteins; D017392:Thiobarbituric Acid Reactive Substances; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases