Abstract
Our results demonstrate that the organic hydroperoxide t-butyl-hydroperoxide (TBHP) influences the synthesis of prostaglandins in the human embryo lung fibroblast. TBHP inhibits or stimulates prostaglandin synthesis as a function of its concentration. Regardless of the concentration employed in these experiments however, TBHP stimulated the release of arachidonate from lipid stores. When the arachidonate release step in prostaglandin (PG) synthesis was bypassed by the addition of free arachidonate to the cell cultures, t-butyl hydroperoxide further stimulated PG synthesis, indicating that the hydroperoxide activates arachidonate conversion to prostaglandins. 4-Hydroxy-2,2,6,6-tetramethylpiperidinoxy radical, a scavenger of oxygen radicals, when added to cell cultures alone had no measurable effect on either arachidonate release or prostaglandin synthesis. When 4-hydroxy-2,2,6,6-tetramethylpiperidinoxy radical was administered to cell cultures in combination with t-butyl hydroperoxide, it increased prostaglandin synthesis while inhibiting arachidonate release by the hydroperoxide. The participation of hydroperoxides and trappers of oxygen radicals in the regulation of PG synthesis is not unique to lung fibroblasts. Endothelial cells from the vasculature as well as fibroblasts from the cornea also appear to be affected by these compounds with respect to prostaglandin synthesis.
Highlights
Our results demonstratethattheorganichydroascorbate activates PG synthesis[5].This activation appears peroxide t-butyl hydroperoxide (TBHPi)nfluences the to proceed through the generation of HzOz[6]
Assay for Prostaglandins-Antibodies to PGE,PGF2, 6-ketoPGF, and TXBz were prepared in rabbits as described previously [6].Cross-reactivities of any of the antisera against nontargeted PGs appear to potentiate the synthesis of PGs through the fatty were less than 5% [6]
Our results demonstrate that hydroperoxide molecules inhibit or promote prostaglandin synthesis in lung fibroblasts in a concentration-dependent manner
Summary
Confluent cultures were made tetramethylpiperidinoxy radical was administered to quiescent by incubation in MEM containing 0.5% serum for 3 days cell cultures in combination with t-butyl hydroperox- before experiments. Previous studies have shown that quiescent cells ide, it increased prostaglandin synthesis while inhibiting arachidonate release by the hydroperoxide. Release of ~H/Arachid~nute-[~H]Arachidonicacid (95.4 Ci/mol) in ethanol was purchased from New England Nuclear It was diluted in culture medium containing 2% fetal bovine serum to a concentration of 2.5 X lo cpm/100 pl. It was added (100 pl/dish) to the cells. &Butyl hydroperoxide has a regulatory effect on PG synthesis in the human embryo lung fibroblast
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