In vivo effects of indomethacin on the activity of metal-containing enzymes.

1. Indomethacin injected subcutaneously at a single "ulcerogenic" dose decreased aminooxidase and leucine aminopeptidase activity and did not change alcohol dehydrogenase and ceruloplasmin activity. 2. Indomethacin administered at an oral "therapeutic" dose inhibited aminooxidase activity in small intestinal mucosa but not in liver and did not change leucine aminopeptidase activity in blood, liver and intestinal mucosa; it, however, increased alcohol dehydrogenase and ceruloplasmin activity. 3. The decreased activity of ceruloplasmin and alcohol dehydrogenase by metal deficiency increased after oral indomethacin treatment, reaching the control values when indomethacin was chelated with copper. 4. The results suggest the participation of endogenous metals in the indomethacin effect.