Electrophoretic analysis of normal and regenerating rat liver membrane proteins

It is known that the cell surface of transformed cells shows a composition different from that of normal cells. Since the growth response is one of the parameters which appears to be altered, i.e. transformed cells continue to proliferate under such conditions in which normal cells do not, each alteration of the membrane connected with transformation could be involved in proliferation control mechanisms. Therefore such modifications could be expected to occur also in normal cells undergoing mitotic stimulations. Our work aimed to test whether this hypothesis is true also in the case of regenerating liver following partial hepatectomy. Electrophoresis was performed with polyacrylamide gel additioned with SDS in liver membranes from rats partially hepatectomized from 4h, 15h and 24h and solubilized with different detergents (solutions A, B and C). From the results we observed that liver membranes from 4h hepatectomized rats show a decrease in the amount of high molecular weight proteins; the appearance of two additional bands with molecular weight about 40,000 was also detected. At 15h after operation we observed a percent increase in the high molecular weight areas and a decrease in the low molecular weight one.