Perivenous localisation of Na-dependent glutamate transport in perfused rat liver.
Periportal and perivenous hepatocytes differ in their metabolism of blood glutamate (Glu). Uncertainty about the mechanisms of Glu blood-liver exchange led us to characterise, by paired-tracer dilution, a sodium-dependent dicarboxylate transporter (resembling system X-ag) in sinusoidal membranes of perfused rat liver (Vmax = 0.18 mumol Glu/g per min, Km = 0.29 mM Glu). Tracer Glu transport was depressed 65% after necrosis of perivenous hepatocytes by acute CCl4 treatment, indicating that X-ag transporter activity is located mainly in these cells, the sites of glutamine (Gln) synthesis from glutamate and ammonia. Modulation of Glu transport may influence the extent of hepatic Gln release.
D000818:Animals; D001692:Biological Transport; D005260:Female; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D005973:Glutamine / Q000096:biosynthesis; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D010477:Perfusion; D011169:Portal Vein / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000494:pharmacology*
D005971:Glutamates; D005973:Glutamine; D018698:Glutamic Acid; D012964:Sodium