Kinetic evidence of a surface membraneous step during the endocytosic process of 3H-labelled asialoorosomucoid and its alteration in diabetic mellitus rats.
The apparent internalization rate constant of asialoorosomucoid in normal and diabetic hepatocytes was determined using different experimental processes, either following a synchronous wave of prebound ligand or a continuous flux ligand endocytosis, either alone or simultaneously. In continuous flux conditions, no difference between normal and diabetic hepatocytes appeared (k = 0.15 +/- 0.04 and 0.11 +/- 0.02 min-1, respectively). In contrast, in the one-turn endocytosis of prebound ligand, k was lower for diabetic hepatocytes than for normal ones whether it was measured alone (0.20 +/- 0.03 and 0.59 +/- 0.09 min-1, respectively) or simultaneously with a continuous flux of unlabelled ligand (0.25 +/- 0.03 and 0.70 +/- 0.08 min-1, respectively). These differences are attributed to an impediment or a delay in the preclustering of receptors in coated pits at the cell surface of diabetic cells.
D000818:Animals; D037263:Asialoglycoprotein Receptor; D001212:Asialoglycoproteins; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004705:Endocytosis; D007700:Kinetics; D008024:Ligands; D008099:Liver / Q000378:metabolism*; D009961:Orosomucoid / Q000031:analogs & derivatives* / Q000378:metabolism; D051381:Rats; D011971:Receptors, Immunologic / Q000378:metabolism*
D037263:Asialoglycoprotein Receptor; D001212:Asialoglycoproteins; D008024:Ligands; D009961:Orosomucoid; D011971:Receptors, Immunologic; C017030:asialoorosomucoid