Maintenance of monooxygenase activities and detection of cytochrome P-450-mediated cytotoxicity in Mongolian gerbil hepatocyte cultures.
1. Hepatocytes were isolated from untreated and phenobarbitone (PB)-treated Mongolian gerbils by lobe perfusion. Yields were approx. 20 x 10(6) cells/g liver and viability was 95 +/- 1%. 2. PB treatment significantly increased the total cytochrome P-450 content, and the 7-ethoxycoumarin O-deethylase, p-nitrophenol hydroxylase and coumarin 7-hydroxylase activities, relative to those of untreated gerbils, measured in homogenates of freshly isolated hepatocytes. 3. After 24 h in culture the cytochrome P-450 content of hepatocyte homogenates from both untreated and PB-treated gerbils was 40-45% that of the corresponding values of freshly isolated hepatocytes. This decrease was accompanied by selective losses of cytochrome P-450-dependent enzyme activities. 4. Erythromycin and benzphetamine N-demethylase, and p-nitrophenol hydroxylase, activities were well maintained over 24 h in culture, whilst 7-ethoxycoumarin O-deethylase and coumarin 7-hydroxylase activities were poorly maintained. In general, the stability of the monooxygenase activities measured was improved by BP treatment of gerbils. 5. The toxicity of coumarin, precocene I and precocene II to gerbil hepatocyte cultures was dose-dependent. Precocene II was significantly more toxic to hepatocytes cultured from PB-treated, compared with untreated, gerbils. 6. Gerbil hepatocyte cultures would seem to be appropriate for investigating species differences in metabolism-mediated cytotoxicity.
Fentem
J H
JH
Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham, UK.
Hammond
A H
AH
Fry
J R
JR
D000818:Animals; D001578:Benzopyrans / Q000633:toxicity; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D003374:Coumarins / Q000633:toxicity; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005849:Gerbillinae; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology
D001578:Benzopyrans; D003374:Coumarins; C014163:precocene II; C019539:precocene I; D003577:Cytochrome P-450 Enzyme System; C030123:coumarin; D006899:Mixed Function Oxygenases; D010634:Phenobarbital