Uptake and degradation of desialylated luteinizing hormone by suspended hepatocytes.
The uptake and degradation of desialylated human luteinizing hormone (asialo-LH) in suspended hepatocytes have been studied. Asialo-LH was taken up by the asialo-glycoprotein receptor at a rate which was somewhat lower than that of asialo-fetuin. The rate constants and equilibrium binding parameters were similar, but the rate of dissociation of the receptor-ligand complex was higher in the case of asialo-LH. The uptake was influenced by heterogeneity of the asialo-LH preparation. Degradation of endocytosed asialo-LH took place in the lysosomes. After fractionation of the cells by isopycnic centrifugation in a sucrose gradient, partially degraded asialo-LH (precipitable with trichloracetic acid, but not with antibody) was found in the fractions containing endocytic vesicles, but not in the lysosomal fractions, indicating that the proteolysis of asialo-LH was initiated in the endocytic vesicles.
D000818:Animals; D001212:Asialoglycoproteins; D001692:Biological Transport / Q000187:drug effects; D002738:Chloroquine / Q000494:pharmacology; D003078:Colchicine / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology; D060748:Fetuins; D007700:Kinetics; D007976:Leupeptins / Q000494:pharmacology; D008099:Liver / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000031:analogs & derivatives* / Q000378:metabolism; D008297:Male; D051381:Rats; D000509:alpha-Fetoproteins / Q000378:metabolism
D001212:Asialoglycoproteins; D060748:Fetuins; D007976:Leupeptins; D000509:alpha-Fetoproteins; C017029:asialofetuin; C034581:luteinizing hormone, desialylated; D003571:Cytochalasin B; D002738:Chloroquine; D007986:Luteinizing Hormone; D003078:Colchicine