Promutagen activation with mammalian and avian S9 liver microsomes

Area of Science:

• Biochemistry
• Toxicology
• Genetics

Background:

• Metabolic activation is crucial for understanding xenobiotic metabolism and toxicity.
• Aroclor 1254-induced rat liver microsomes (S9) are commonly used to assess metabolic activation.
• Investigating alternative S9 sources, like domestic animal livers, is important for broader toxicological studies.

Purpose of the Study:

• To compare the metabolic activation potential of uninduced domestic animal liver S9 with induced rat liver S9.
• To evaluate the impact of freeze-drying and reconstitution on chicken liver S9 activity.

Main Methods:

• Utilized the Ames Salmonella typhimurium mutagenesis assay (strains TA98 and TA100).
• Assessed metabolic activation of promutagens benzo(a)pyrene and 2-aminoanthracene.
• Compared S9 fractions from beef, pig, sheep, chicken, and induced rat livers.

Main Results:

• Chicken liver S9 demonstrated the highest promutagen activation levels.
• S9 from other domestic animals showed activity comparable to induced rat S9.
• Freeze-dried and reconstituted chicken S9 exhibited enhanced metabolic activation.

Conclusions:

• Chicken liver S9 is a highly effective source for metabolic activation studies.
• Domestic animal S9 fractions offer viable alternatives to rat S9.
• Processing methods like freeze-drying can optimize S9 preparation for enhanced activity.