title: Quantitative microspectrofluorimetry study of the "blocking effect" of 6-aminochrysene on benzo[a]pyrene metabolism using single living cells.
abstract: By microspectrofluorimetry on single living cells (murine fibroblasts 3T3), we have obtained monoexponential decreases of fluorescence intensity for benzo[a]pyrene (B[a]P) and 6-aminochrysene (6a-chrysene) metabolism. These kinetics are characteristics of B[a]P and 6a-chrysene metabolism and histograms can be drawn from the rate constants. We have studied the influence of 6a-chrysene on B[alpha]P metabolism. Using different methods of incubation, it has been observed that the presence of 6a-chrysene leads to modifications of the histogram profiles during B[a]P metabolism. Polycyclic aromatic hydrocarbons (PAH) are used to induce B[a]P metabolism. Whatever the experimental conditions we never detected such a phenomenon with 6a-chrysene. On the contrary we have observed an inhibition of B[a]P metabolism by 6a-chrysene, which can reach 80% of the aryl hydrocarbon hydroxylase (AHH) activity when 6a-chrysene remains constant in the cells. Compared with the results previously observed "in vitro" which presented 50% mean inhibition) we show that inhibition acts in an all-or-nothing mechanism at the cellular level.
mesh_terms: D000818:Animals; D001564:Benzo(a)pyrene; D001580:Benzopyrenes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002911:Chrysenes; D005347:Fibroblasts / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D010616:Phenanthrenes / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence
chemical_list: D001580:Benzopyrenes; D002911:Chrysenes; D010616:Phenanthrenes; D001564:Benzo(a)pyrene; C100101:6-chrysenamine