USE OF FRESH AND CRYOPRESERVED HEPATOCYTES TO STUDY THE METABOLISM OFPESTICIDES IN FOOD-PRODUCING ANIMALS AND RATS

1. The possibility of using hepatocytes from food-producing animals in order to determine the metabolic routes of pesticides has been studie d using a strobilurin fungicide (BAS 490 F). Hepatocytes suspensions w ere prepared from goat, pig, hen, and rat and the major metabolites we re compared with those obtained in vivo. 2. The hepatocytes gave metab olite patterns matching qualitatively with in vivo results, but no goo d quantitative correlation was found. 3. A freezing and thawing method was developed using liquid nitrogen and programmable freezer, which a llows acceptable recoveries of functional cells as assessed by glutath ione and cytochrome P450 contents, and phase I and II enzymatic activi ties (including 7-ethoxycoumarin-O-deethylase, ethoxyresorufin-O-deeth ylase, glutathione-S-transferase, and UDP-glucuronosyl transferase), w ith 60-70% viability. 4. The cells were damaged through freezing as in dicated by the efflux of glutathione (40-60% of the intracellular cont ent), but remained able to metabolize BAS 490 F, partially like fresh cells. A good qualitative but no quantitative matching of the metaboli te patterns before and after cryopreservation was found, indicating th at the metabolic activities are affected to variable extents during th e freezing process. 5. The use of fresh and cryopreserved cells as mod els for metabolism and species comparison, and as a versatile tool to synthesize metabolites, is discussed.