Effects of acetylenic and olefinic pyrenes upon cytochrome P-450 dependent benzo[a]pyrene hydroxylase activity in liver microsomes

Biochem Biophys Res Commun. 1985 Jun 14;129(2):591-6. doi: 10.1016/0006-291x(85)90192-5.

Abstract

1-Ethynylpyrene, trans-, & cis-1-(2-bromovinyl)pyrene, methyl 1-pyrenyl acetylene, and phenyl 1-pyrenyl acetylene are substrates for cytochrome P-450 dependent monooxygenases and also inhibitors of cytochrome P-450 dependent benzo[a]pyrene hydroxylase activities in liver microsomes from 5,6-benzoflavone or phenobarbital pretreated rats. 1-Ethynylpyrene, trans-1-(2-bromovinyl)pyrene, and methyl 1-pyrenyl acetylene cause a mechanism based inhibition (suicide inhibition) of the benzo[a]pyrene hydroxylase activities in microsomes from 5,6-benzoflavone or phenobarbital pretreated rats, while cis-1-(2-bromovinyl)pyrene only causes suicide inhibition of the hydroxylse activities in the 5,6-benzoflavone induced microsomes and phenyl 1-pyrenyl acetylene does not cause a detectable suicide inhibition of these activities in either type of microsome. Incubation with NADPH and 1-ethynylpyrene, trans-, or cis-1-(2-bromovinyl)pyrene causes a loss of the P-450 content in the microsomes from 5,6-benzoflavone or phenobarbital pretreated rats, but incubations with methyl 1-pyrenyl acetylene or phenyl 1-pyrenyl acetylene did not cause a loss of the P-450 content of either microsomal preparation.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Aryl Hydrocarbon Hydroxylases / antagonists & inhibitors*
  • Benzoflavones / pharmacology
  • Benzopyrene Hydroxylase / antagonists & inhibitors*
  • Cytochrome P-450 Enzyme System / metabolism*
  • In Vitro Techniques
  • Microsomes, Liver / drug effects
  • Microsomes, Liver / enzymology*
  • Phenobarbital / pharmacology
  • Pyrenes / pharmacology*
  • Rats
  • Structure-Activity Relationship
  • beta-Naphthoflavone

Substances

  • Benzoflavones
  • Pyrenes
  • beta-Naphthoflavone
  • Cytochrome P-450 Enzyme System
  • Benzopyrene Hydroxylase
  • Aryl Hydrocarbon Hydroxylases
  • Phenobarbital