Z protein in hepatic uptake and esterification of long-chain fatty acids

• Published in: The American journal of physiology Vol. 228; no. 6; p. 1634
• Main Authors: Mishkin, S, Stein, L, Fleischner, G, Gatmaitan, Z, Arias, I M
• Format: Journal Article
• Language: English
• Published: United States 01.06.1975
• Subjects: Animals; Chromatography, Gel; Cytoplasm - metabolism; Esters; Fatty Acids - metabolism; In Vitro Techniques; Liver - analysis; Liver - metabolism; Male; Oleic Acids - metabolism; Phloroglucinol - analogs & derivatives; Phloroglucinol - pharmacology; Protein Binding; Proteins - analysis; Proteins - physiology; Rats; Sulfobromophthalein - pharmacology
• ISSN: 0002-9513
• DOI: 10.1152/ajplegacy.1975.228.6.1634

Fatty acids radioactivity was bound to Z protein in liver after administration of['3H]oleate to rats or to a perfused rat liver preparation. Pretreatment withflavaspidic acid (340 mumol/kg), a potent inhibitor of fatty acid binding to hepatic Zprotein in vitri, effectively reduced oleate radioactivity bound to Z by 90.2 plusor minus 4.3% and 85.0 plus or minus 6.2% in the intact rat and perfused liver, respectively. In spite of this effect, pretreatment of rats with flavaspidic acid did notalter plasma clearance, hepatic uptake, and esterification of ['3H]oleate. In contrast, in the perfused liver preparation, infusion of flavaspidic acid (340 mumol/kg)or bromosulphalein (360 mumol/kg) increased uptake of ['3H]oleate at least twofold,and oleate esterification was decreased by 15-30%. These results suggest that the binding of long-chain fatty acids to Z protein is not an obligatory step in their uptakeby the liver and that Z protein may be involved in fatty acid esterification.