Uptake and degradation of asialo-fetuin by isolated rat hepatocytes.
125I-labelled asialo-fetuin was taken up by isolated rat hepatocytes by a saturable process. Half maximum uptake was seen at about 3 . 10(-8) M asialo-fetuin. Rate of uptake of asialo-fetuin exceeded rate of degradation at all concentrations of asialo-fetuin tested. Degradation of asialo-fetuin, as indicated by release of acid-soluble radioactivity from the cells, was inhibited by NH4Cl and chloroquine. The intracellular distribution of labelled asialo-fetuin was studied by differential and density gradient centrifuging. The distribution curves for radioactivity indicated that asialo-fetuin was present in lysosomes about 1 h after the uptake had started. Chloroquine and ammonium ions seemed to inhibit the uptake of asialo-fetuin into the lysosomes, possibly by interfering with the fusion between phagosomes and lysosomes.
D000118:Acetylglucosaminidase / Q000378:metabolism; D000641:Ammonia / Q000494:pharmacology; D000818:Animals; D001212:Asialoglycoproteins; D001692:Biological Transport; D002738:Chloroquine / Q000494:pharmacology; D060748:Fetuins; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008247:Lysosomes / Q000378:metabolism; D008297:Male; D051381:Rats; D012794:Sialic Acids; D000509:alpha-Fetoproteins / Q000378:metabolism*
D001212:Asialoglycoproteins; D060748:Fetuins; D012794:Sialic Acids; D000509:alpha-Fetoproteins; C017029:asialofetuin; D000641:Ammonia; D002738:Chloroquine; D000118:Acetylglucosaminidase