Liver postmitochondrial supernatant

Figure 4. Toxic and mutagenic response of diploid human lymphoblast line MIT-2 to aflatoxin B,. Open symbols afatoxin + phenobarbital-induced rat liver postmitochondrial supernatant (PMS) closed symbols effect of treatment with either aflatoxin or FMS alone.

NPYR Rat Liver microsomes and postmitochondrial supernatant identification of 1,4-butanediol, and 4-hydroxybutyric acid 12... 

NPYR Rat Liver and lung microsomes and postmitochondrial supernatant a-hydroxylation but not p-hydroxy-lation in both tissues 13... 

Analysis of the products formed from NHEX in vitro using rat liver microsomes and postmitochondrial supernatant resulted in the identification of 3-hydroxyNHEX from p-hydroxylation and 4-hydroxyNHEX from y-hydroxylation. The ratio of 4-hydroxyNHEX to 3-hydroxyNHEX was 3 to 1. Both conformeric forms of each of these metabolites were detected (53). From ix vitro data which are available so far for NPYR, NNN, NPIP, and NHEX, it does appear that the rates of a- and y-hydroxylation (when possible), exceed those of p-hydroxylation. 

Ames Test The Ames test, developed by Bruce Ames and his coworkers at the University of California, Berkeley, depends on the ability of mutagenic chemicals to bring about reverse mutations in Salmonella typhimurium strains that have defects in the histidine biosynthesis pathway. These strains will not grow in the absence of histidine but can be caused to mutate back to the wild type, which can synthesize histidine and hence can grow in its absence. The postmitochondrial supernatant (S-9 fraction), obtained from homogenates of livers of rats previously treated with PCBs in order to induce certain cytochrome P450 isoforms, is also included in order to provide the activating enzymes involved in the production of the potent electrophiles often involved in the toxicity of chemicals to animals. 

If mutagenesis is determined in the Salmonella/microsome test, the degree of positive or negative findings is based on toxification by the postmitochondrial supernatant fraction from the liver of rats previously treated with Aroclor 1254. Likewise, any mutagenicity index for a... 

A postmitochondrial supernatant from rat liver is most commonly used today.181 Because in principle it would mimic the human situation, human material would be preferred, but it is not practical, both because of the difficulty in obtaining material and because humans cannot be given the chemicals used for metabolic induction in the rat. 

Source Table adapted from http //www.fda.gov/cder/guidance/6695dft.pdf. a Microsomes, liver microsomes S9, postmitochondrial supernatant. 

Postmitochondrial supernatant (S-9) of Sprague Dawley rat liver induced with Aroclor 1254 was purchased from Molecular Toxicology, Inc., stored at -80 C, and thawed on ice prior to use. A cofactor solution of 78 mM sodium phosphate, pH 7.2, 117 mM NaCl, 7.8 mM glucose-6-phosphate, monosodium salt, 5.9 mM P-NADP, sodium salt, 11.4 mM MgCl2, 47 mM KCl, was made by minor modification of a previous meAod (43), filter sterilized, stored at -80 C, and Aawed on ice prior to use. 

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