Density shift of endocytic vesicles induced by uptake of colloidal gold particles in rat hepatocytes

The aim of this study was to demonstrate the influence of endocytosed asialoorosomucoid gold complexes (ASOR-Au10, 10 = diameter of gold particles) on the density of endocytic compartments in rat hepatocytes when fractionated on linear sucrose gradients. We show that by loading hepatocytes with ASOR-Au10 for different time intervals, organelles containing gold particles are denser than organelles containing unconjugated asialoorosomucoid (ASOR). This density shift was observed in endosomes, which were loaded with a short pulse (15 minutes) of ASOR- Au10. Also lysosomes, loaded with ASOR-Au10 for 120 minutes at 37 degrees C, display a similar density shift.