[Influence of metals and non-steroid anti-inflammatory drugs on the activity of human red cell ALA dehydratase "in vitro" (author's transl)].

The effect of metals and drugs on the activity of human erythrocyte ALA dehydratase has been studied in vitro. The most inhibitory metals are with decreasing effect silver, copper, gold and selenium. Zinc, cadmium, mercury are inhibitory at high concentrations and activator at low concentrations. Arsenic, calcium, magnesium, manganese, potassium, cobalt have no effect. Within the drugs studied the non steroidal anti-inflammatory drugs (aspirin, keptoprofen, indometacin, phenylbutazone, sodium salicylate and niflumic acid) are the only group which inhibits the enzyme ALA dehydratase. This inhibition is suppressed by zinc. The non steroidal anti-inflammatory drugs can inhibit the activity of enzymes which need zinc for optimal activity.