The effects of free radical scavengers on arachidonic acid metabolism by ovine placental microsomes.
1. The effect of free radical (superoxide and hydroxyl) and hydrogen peroxide scavengers on the formation of prostaglandin E2 by ovine placental microsomes was investigated. 2. Of the free radical scavengers tested only Mn Desferal, a low molecular weight (712 Da) superoxide scavenger, at concentrations of 0.5-5 mmol/l significantly (P less than 0.001) stimulated PGE2 formation by ovine placental microsomes. 3. This observation is consistent with the involvement of superoxide radicals in the inactivation of prostaglandin G/H synthase (PGHS). 4. The results obtained further suggest that if superoxide radicals are important regulators of PGHS activity in the ovine placenta, they are not accessible to large molecular weight free radical scavengers.
Rice
G E
GE
Department of Physiology, Monash University, Clayton, Victoria, Australia.
Baker
M S
MS
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D005260:Female; D016166:Free Radical Scavengers; D066298:In Vitro Techniques; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism*; D008970:Molecular Weight; D010101:Oxygen Consumption / Q000187:drug effects; D010920:Placenta / Q000187:drug effects / Q000378:metabolism*; D011453:Prostaglandins / Q000096:biosynthesis; D012756:Sheep / Q000378:metabolism*
D016861:Cyclooxygenase Inhibitors; D016166:Free Radical Scavengers; D011453:Prostaglandins; D016718:Arachidonic Acid