title: Stability of Aroclor 1254-induced rat liver postmitochondrial supernatant (S-9) following long-term storage (-75 degrees C).
abstract: The stability of Aroclor 1254-induced rat liver postmitochondrial supernatant (S-9) over a 5-year period was investigated in a retrospective study. S-9 was uniformly prepared at 6-month intervals, and aliquots were stored at -75 degrees C. The protein and cytochrome P-450 content of these lots of S-9 were very similar, and no differences attributable to duration of storage were observed in the activities of ethoxycoumarin O-deethylase, aniline hydroxylase, cytochrome P-450 reductase or aryl hydrocarbon hydroxylase. There was no decrease following 5 years of storage in the ability of S-9 to activate 2-aminoanthracene, as measured in the Ames test (TA98), but there was a notable reduction following more than 1 year of storage in the ability of the S-9 to generate Ames test activity with benzo(a)pyrene. Based on the results of these studies, S-9 prepared and stored under these conditions appears to be suitable for use in vitro genotoxicity assays for at least 1 year.
mesh_terms: D015660:7-Alkoxycoumarin O-Dealkylase; D000815:Aniline Hydroxylase / Q000096:biosynthesis; D000818:Animals; D001140:Aroclors / Q000494:pharmacology*; D001189:Aryl Hydrocarbon Hydroxylases / Q000096:biosynthesis; D020111:Chlorodiphenyl (54% Chlorine); D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis; D004790:Enzyme Induction; D005615:Freezing; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism*; D008297:Male; D009152:Mutagenicity Tests; D009153:Mutagens; D010105:Oxygenases / Q000096:biosynthesis; D011078:Polychlorinated Biphenyls / Q000494:pharmacology*; D011309:Preservation, Biological; D051381:Rats; D012486:Salmonella typhimurium / Q000235:genetics; D013048:Specimen Handling; D013347:Subcellular Fractions / Q000378:metabolism*
chemical_list: D001140:Aroclors; D009153:Mutagens; D020111:Chlorodiphenyl (54% Chlorine); D003577:Cytochrome P-450 Enzyme System; D011078:Polychlorinated Biphenyls; D010105:Oxygenases; D015660:7-Alkoxycoumarin O-Dealkylase; D000815:Aniline Hydroxylase; D001189:Aryl Hydrocarbon Hydroxylases