Isolation of Periportal and Pericentral Hepatocytes

Liver parenchyma shows a remarkable heterogeneity of the hepatocytes along the porto-central axis, particularly with respect to the expression of cytochromes P450 and other enzymes involved in the biotransformation and conjugation of xenobiotics (1 and references therein). This mlcrodiversity is best revealed by immunohistochemical techniques or by in situ hybridization on liver sections. However, when the focus is on metabolic activitles, straightforward access to heterogeneity is via isolation of hepatocyte subpopulations. Because of the considerable variability of enzyme distribution, it is impossible to design a separation technique that accounts for every kind of metabolic zonation. However, the rough separation of the hepatocytes into two subpopulations, namely the perlportal and the pericentral populations, provides a suitable approach to studying many aspects of hepatocyte heterogeneity in drug metabolism. Several techniques have been established for the separation of periportal and pericentral hepatocytes. The most suitable separation technique leading to consistent results is the so-called digitonin-collagenase perfusion method developed independently by Quistorff (2 ) and Lindros and coworkers (3 ). Based on the dlstrtbutlon of clearly zonated enzymes, such as glutamme synthetase, a reasonable enrichment of both cell populations could be demonstrated (4 ).