Chronic inhalation effects of ethylene oxide on porphyrin-heme metabolism.
The effects of chronic ethylene oxide (EtO) inhalation on porphyrin-heme metabolism were investigated. When Wistar male rats were exposed to 500 ppm EtO for 6 h a day, 3 times a week for 13 weeks, hemoglobin content significantly decreased, and a normocytic and normochromic anemia was found. In the liver, cytochrome P-450 and protoheme significantly decreased but wet weight, microsomal protein and cytochrome b5 were not affected. The activity of delta-aminolevulinic acid (ALA) synthase increased while ALA dehydratase did not change. The activity of hepatic ferrochelatase decreased time-dependently. Uroporphyrin increased 37% and coproporphyrin tended to increase in the liver. The concentration of protoporphyrin in the liver and erythrocytes tended to increase. Coproporphyrin excretion in the urine showed a 5-6-fold increase while there was no significant increase in urinary ALA excretion. These results indicate that chronic inhalation of EtO causes alterations of hepatic porphyrin-heme metabolism as well as anemia and may affect mechanisms of adaptation to xenobiotics.
Fujishiro
K
K
Department of Environmental Toxicology, University of Occupational and Environmental Health, Kitakyusyu, Japan.
Mori
K
K
Inoue
N
N
D000624:5-Aminolevulinate Synthetase / Q000378:metabolism; D000280:Administration, Inhalation; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D005027:Ethylene Oxide / Q000008:administration & dosage / Q000633:toxicity*; D006403:Hematologic Tests; D006415:Hematoporphyrins / Q000378:metabolism* / Q000652:urine; D006418:Heme / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains
D006415:Hematoporphyrins; D006418:Heme; D003577:Cytochrome P-450 Enzyme System; D000624:5-Aminolevulinate Synthetase; D005027:Ethylene Oxide