Differential stabilization of cytochrome P-450 isoenzymes in primary cultures of adult rat liver parenchymal cells

Abstract

Cytochrome P-450 dependent hydroxylation of testosterone was measured in 7-day-old cultures of primary rat liver parenchymal cells. Determinations were carried out in monocultures of parenchymal cells and co-cultures of parenchymal cells with rat liver nonparenchymal epithelial cells, or mouse embryo fibroblasts. In the monoculture system, testosterone metabolism was drastically reduced and hardly measurable after 7 days in culture. In the co-culture systems, individual P-450 isoenzymes were stabilized on different levels. P-450s p and presumably c were well preserved, P-450 a was reduced but clearly measurable, P-450 h was totally lost whereas P-450s b and e were not measurable after 7 days (the activities of these isoenzymes however were already low in freshly isolated parenchymal cells). The results were independent of the cell line used for co-cultivation and of the method of parenchymal cell isolation, that is whether collagenase or EDTA was used as the agent for dissociating the cells from the liver. The results showed that the co-cultivation of liver parenchymal cells with other nonparenchymal cells significantly improved the differentiated status of the former. In this cell culture system however, not every parameter was equally well stabilized.

Liver cell models in in vitro toxicology.

“…These two features could be related because in pure hepatocyte cultures the addition of proteoglycans improves gap junction activity (137). The enhanced survival and function of hepatocytes cocultured with rat liver epithelial cells have been confirmed by many investigators (134,(138)(139)(140)(141)(142)(143); the induction of CYP2B1 and CYP2B2 by phenobarbital has also been demonstrated (137,144). Moreover, other cells have been effective, including both liver endothelial cells and nonhepatic cells (145)(146)(147).…”

Effects of sodium butyrate on DNA content, glutathione S-transferase activities, cell morphology and growth characteristics of rat liver nonparenchymal epithelial cells in vitro

“…NEC establishment and culture NEC were initiated as described before (16). In brief, thin liver slices from an adult, male Sprague-Dawley rat were repeatedly digested with trypsin.…”

“…why were GST activities increased and not those of UDPGT, or how the changes on the DNA level are linked to the changes in enzyme activities or cell size. Experience has shown (14,16) that single physiological parameters that are crucial for the differentiated status of a given cell type in vitro may be regulated independently and, thus, may respond differently to external factors. Furthermore, different types of cells react differently to agents such as sodium butyrate.…”

Regulation of the Major Detoxication Functions by Phenobarbital and 3‐Methylcholanthrene in Co‐Cultures of Rat Hepatocytes and Liver Epithelial Cells

“…Indeed, a co-culture model of primary hepatocytes and rat liver epithelial cells has been developed in our laboratory ; this has been used in pharmaco-toxicological studies and remains one of the most effective and practical experimental approaches to obtain extended hepatocyte survival and functional activity. Although several reports have demonstrated expression of biotransformation activities in this system (BCguC et al, 1983(BCguC et al, , 1993Niemann et al, 1991;Perrot et al, 1991;Utesch et al, 1991;Donato et al, 1994), limited data are yet available with regard to CYP mRNA expression. Akrawi et al (1993) have shown that co-cultures maintained mRNAs encoding CYP2BlI 2, CYPlA2, NADPH: cytochrome P-450 reductase and cytochrome b,, together with a significant induction of CYP2B mRNA and protein following exposure to phenobarbital.…”