Drug metabolism by periportal and perivenous rat hepatocytes. Comparison of phase I and phase II reactions and their inducibility during culture

Hepatocytes were aseptically isolated from either the periportal (pp; zone 1) or the perivenous (pv; zone 3) region by digitonin-collagenase perfusion and cultured on type I collagen for 4 to 9 days. In freshly isolated cells the pp:pv activity ratios of the acinar marker enzymes gamma-glutamyltrans...

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Bibliographic Details
Published in:	Biochemical pharmacology Vol. 38; no. 8; p. 1329
Main Authors:	Suolinna, E M, Penttilä, K E, Winell, B M, Sjöholm, A C, Lindros, K O
Format:	Journal Article
Language:	English
Published:	England 15-04-1989
Subjects:	7-Alkoxycoumarin O-Dealkylase Alanine Transaminase - metabolism Animals Cells, Cultured Enzyme Induction gamma-Glutamyltransferase - metabolism Glucuronosyltransferase - metabolism Glutamate Dehydrogenase - metabolism Glutathione Transferase - metabolism Hepatic Veins Hymecromone - metabolism Liver - cytology Liver - enzymology Liver - metabolism Male Oxygenases - metabolism Portal Vein Rats Xenobiotics - metabolism
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Summary:	Hepatocytes were aseptically isolated from either the periportal (pp; zone 1) or the perivenous (pv; zone 3) region by digitonin-collagenase perfusion and cultured on type I collagen for 4 to 9 days. In freshly isolated cells the pp:pv activity ratios of the acinar marker enzymes gamma-glutamyltranspeptidase (gamma-GT), alanine aminotransferase (ALAT) and glutamate dehydrogenase (GLDH) were 2.8, 1.6 and 0.76, respectively. During culture ALAT and GLDH activities gradually declined, but the pp-pv difference was retained for at least 4 days. In contrast, the difference in the gamma-GT activity was rapidly lost, due to its fast initial activation in pv cells. The initial 7-ethoxycoumarin O-deethylase (ECDE) activity was higher in pv cells; this difference was retained for several days of culture and was increased by induction in vitro with either phenobarbital (PB) or beta-naphthoflavone (beta NF). Although the basal UDP-glucuronyltransferase (UDPGT) activity with either p-nitrophenol (pNP) or hydroxybiphenyl (HBP) as substrate did not differ significantly, the in-vitro PB- or beta NF-induced activity was higher in pv cells. Both glucuronidation and sulfation of methylumbelliferone tended to be higher in pv cells. Glutathione S-transferase was initially significantly higher in pv cells and this difference was augmented after in vitro induction by PB or beta NF. After six days in culture all the observed pp-pv differences had disappeared. These results suggest that hepatocytes isolated from the perivenous region seem to maintain their initially higher capacity for phase I and phase II drug reactions during culture and also respond more strongly than periportal cells to in vitro induction.
ISSN:	0006-2952
DOI:	10.1016/0006-2952(89)90340-7