Anti-inflammatory steroids reduce tissue PG synthetase activity and enhance PG breakdown

Abstract

Antiinflammatory steroids reduce prostaglandin (PG) synthesis in intact cells and isolated organs by interfering indirectly with the phospholipase(s) which release the polyunsaturated fatty acid precursors for both cyclooxygenase and lipoxygenase pathways. This action requires nucleic acid transcription and synthesis of new protein and a soluble factor capable of inhibiting PG generation was identified. It is not known whether steroids affect the actions or content of the enzymes of the PG system after administration in vivo or if they affect PG-metabolizing enzymes. Treatment of rats with antiinflammatory steroids causes rapid changes in tissue activities of enzymes which synthesize and inactivate PG with apparent levels reduced and increased, respectively.