Effect of vitamin A deficiency on pulmonary and hepatic in vitro metabolism of benzo(a)pyrene in rat.
The metabolism of (3H)-benzo(a)pyrene and the activities of enzymes involved in its metabolism were studied in rat lung and liver in vitamin A deficiency. Deficiency of vitamin A resulted a significant decrease in the overall metabolism of benzo(a)pyrene in the liver in vitro, whereas no significant difference was evident in the lung. The ethyl acetate-soluble metabolites of benzo(a)pyrene formed by lung and liver preparations were unaltered qualitatively by vitamin A deficiency. However, quantitative analysis revealed that vitamin A deficiency decreased the yield of dihydrodiols, quinones and phenols in liver, and dihydrodiols in lung. The hepatic cytochrome P-450 content, arylhydrocarbon hydroxylase and uridine diphosphate-glucuronosyl transferase activities were reduced, whereas glutathione S-transferase activity was increased in the vitamin A deficient animals. Contrary to this, pulmonary cytochrome P-450 content was above the control values (p less than 0.01) and no alteration in pulmonary arylhydrocarbon hydroxylase activity was observed in vitamin A deficient rats. Uridine diphosphate-glucuronosyltransferase and glutathione S-transferase activities were impaired in lung by inducing vitamin A deficiency. However, no significant difference was evident in the overall metabolism of benzo(a)pyrene by lung supernatants from the two groups.
D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism; D001564:Benzo(a)pyrene / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003579:Cytochrome Reductases / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007700:Kinetics; D008168:Lung / Q000378:metabolism*; D008297:Male; D008861:Microsomes / Q000378:metabolism*; D008862:Microsomes, Liver / Q000378:metabolism*; D009928:Organ Specificity; D051381:Rats; D011919:Rats, Inbred Strains; D014316:Tritium; D014802:Vitamin A Deficiency / Q000378:metabolism*
D014316:Tritium; D001564:Benzo(a)pyrene; D004247:DNA; D003577:Cytochrome P-450 Enzyme System; D001189:Aryl Hydrocarbon Hydroxylases; D003579:Cytochrome Reductases; D014453:Glucuronosyltransferase; D005982:Glutathione Transferase