Prostaglandin synthetase systems of rabbit tissues and their inhibition by nonsteroidal anti-inflammatory drugs.

Prostaglandin synthetase activities in the microsomal fractions of seven rabbit tissues have been partially characterized. All of the microsomal preparations required arachidonic acid, hydroquinone and reduced glutathione for enzymatic activity. The synthetic systems of the renal medulla were most active followed by microsomal preparations from the renal cortex, lung, brain, spleen, uterus and heart. Three structurally distinct nonsteroidal anti-inflammatory drugs, indomethacin, flufenamic acid and aspirin, inhibited the production of prostaglandins by these microsomes. The effectiveness of these drugs depended on the concentration of substrate. When assayed under identical experimental conditions, the inhibiting activity of each of these drugs for the synthetase of each of the tissues was the same.