Hepatic metabolism of heme in rats after exposure to benzene, gasoline and kerosene.

delta-Aminolevulinic acid (ALA) synthetase, delta-ALA dehydratase and heme oxygenase activities were studied in the liver of albino rats, 3 and 20 h after i.p. administration of benzene, gasoline, and kerosene. delta-ALA synthetase activity was increased markedly after benzene administration, while gasoline and kerosene treated groups showed decreased enzyme activity. Inhibition of delta-ALA dehydratase activity was observed in all three groups, but heme oxygenase activity was unchanged.