Activation of cyclooxygenases by H2O2 and t-butylhydroperoxide in aged rat lung.
The arachidonate cascade is important for the generation of reactive species (RS), and cyclooxygenase (COX) is a key enzyme of this cascade. Tissues of 24-month-old rat lung showed a 2-fold increase in RS, malondialdehyde and thromboxane B2 than those of 6-month-old rat. We found that the effects of 50 microM H2O2 and 200 microM t-butylhydroperoxide (t-BHP) specify on COX activity, and that their effects increased cytosolic COX activity in a concentration-dependent manner (1-50 microM) in 24-month-old rat. Our results suggested that COX activators such as t-BHP and H2O2, which are located in cytosol, are essential for the activation of COX in aged lung.
Im
Jee Won
JW
Department of Pharmacy, Pusan National University, Busan, Korea.
Kim
Hyung Keun
HK
Kim
Nam Deuk
ND
Choi
Jae Sue
JS
Yu
Byung Pal
BP
Yang
Hee-Sun
HS
Chung
Hae Young
HY
D000375:Aging / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008168:Lung / Q000187:drug effects* / Q000201:enzymology*; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D011451:Prostaglandin-Endoperoxide Synthases / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D017382:Reactive Oxygen Species / Q000819:agonists / Q000378:metabolism*; D020122:tert-Butylhydroperoxide / Q000494:pharmacology*
D017382:Reactive Oxygen Species; D020122:tert-Butylhydroperoxide; D006861:Hydrogen Peroxide; D011451:Prostaglandin-Endoperoxide Synthases