Studies on the intercellular adhesion of rat and chicken hepatocytes. Conditions for stimulation by liver plasma membranes.
A new assay was developed for measuring the stimulation of intercellular adhesion of rat hepatocytes by rat liver plasma membranes. Aggregates formed in the presence of the membranes are separated from single cells by filtration, and the number of cells in the aggregates is determined by their lactate dehydrogenase content. The formation of aggregates was specifically stimulated by rat liver plasma membranes and the rate of aggregate formation was proportional to the quantity of added membranes. The effects of divalent cations on the initial rates of rat and chicken hepatocytes adhesion were also examined. Optimal rates of adhesion of rat hepatocytes were obtained in the presence of physiological levels of Mg2+, and adhesion was inhibited by Ca2+, whereas optimal rates of chicken hepatocyte adhesion were obtained in the presence of physiological levels of Ca2+. Plasma membrane stimulation of hepatocyte adhesion also showed the same divalent ion requirements with the respective cell types. The stimulatory activity in the rat plasma membranes determined by the filter assay was found to be sensitive both to trypsin digestion and to mild periodate oxidation. The activity was also completely resistant to vigorous reductive alkylation. These results taken together suggest that the rat plasma membrane stimulatory activity is associated with a glycoprotein(s).
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D002449:Cell Aggregation; D002462:Cell Membrane / Q000502:physiology; D002645:Chickens; D006023:Glycoproteins / Q000502:physiology; D007700:Kinetics; D008099:Liver / Q000502:physiology*; D008274:Magnesium / Q000494:pharmacology; D008565:Membrane Proteins / Q000502:physiology; D008722:Methods; D051381:Rats
D006023:Glycoproteins; D008565:Membrane Proteins; D008274:Magnesium; D002118:Calcium