Partition of rat liver cells in aqueous dextran-polyethylene glycol phase systems

Abstract

Enzyme treatments change the surface charge of cells and thereby affect their partition in two-polymer aqueous phase systems. A mechanical dispersion method was therefore used for the preparation of normal and regenerating rat liver cells although changes in the surface properties of the cells so obtained may also occur. 1. 1. Dextran-polyethylene glycol phase system. The partition coefficient and electrophoretic mobility of regenerating liver cells is higher than that of normal liver cells. Countercurrent distribution of liver cells gives rise to two peaks: the left being larger than the right one for normal cells and the reverse holding for regenerating cells. Liver cells show a correlation between increasing electrophoretic mobilities and increasing partition coefficients through the bulk of the distribution curve. Incubation of liver cells (with 14C-valine) leads to distribution curves that are frequently shifted to the left and distorted but indications are that some separation of differently labeled cells occurs. 2. 2. Dextran-polyethylene glycol phase systems also containing a positively charged polymer. Countercurrent distribution of normal and regenerating liver cells results in single-peak curves. Liver cells from rats injected with india ink particles show a separation of hepatocytes from cells containing india ink particles (histiocytes). The latter are at the extreme right end of the distribution but have lower electrophoretic mobilities than the hepatocytes. Thus the histiocytes probably have a lower electrokinetic charge density than the hepatocytes but a higher charge density in the total peripheral zone (reflected by their partition). Mono- and bi-nucleated liver cells also appear to have different surface properties since their partial separation is effected by countercurrent distribution. Incubation of liver cells (with 14C-valine) does not affect their distribution curves; the more highly radioactively labeled cells are found under the right and left ends.