The effect of prolonged administration of allylisopropylacetylurea to rats on cytochrome P-450 and other liver haemoproteins

1. The effect of long-term administration, including recovery, of allylisopropylacetylurea to rats was investigated. 2. In the liver, cytochromes P-450, b5, catalase and 5-aminolaevulinic acid synthetase were measured. Serum glutamate-pyruvate, transaminase, glutamate-oxalacetate transaminase and alkaline phophatase were determined to assess cell damage, while urinary coproporphyrin and uroporphyrin were measured to assess the degree of porphyia. 3. In the liver the lowering of cytochrome P-450 and catalase was paralleled by an increase in 5-aminolaevulinate synthetase. Cytochrome b5 was only marginally affected. 4. Rats recover well from long-term treatment with high doses of allylisopropylacetylurea and revert to normal values for parameters measured. 5. A mechanism for the intracellular action of allylisopropylacetylurea on cytochrome P-450 and other haem-containing compounds is presented.