Liver uptake of amino acids and carbohydrates during a single circulatory passage.

The uptake of 14C-labeled amino acids and carbohydrates by liver following rapid injection into the portal vein was measured relative to a simultaneously injected highly diffusible reference, tritium-labeled water, (3HOH). A 0.25-ml bolus of buffered Ringer solution containing 1-2 muCi of the 14C-labeled test substance and 3-6 muCi of 3HOH was administered by rabid portal injection in anesthetized rats. Circulation was terminated after a single passage of the bolus through the hepatic microvasculature and the tissue was immediately macerated, solubilized, and subjected to liquid scintillation counting. Liver uptake indices (LUI) were calculated from the ratio of 14C to 3H in liver tissue relative to the same ratio in the injection mixture. LUI's of five carbohydrates were measured: sucrose (24.3 percent), inulin (27.7 percent), D-mannitol (80.2 percent), D-glucose (96.8 percent) and L-glucose (26.7 percent). The LUI for cholic acid was 127.1 percent. Among 18 amino acids tested, the LUI's were the highest for the acidic ones (L-aspartic acid, 100.0 percent and L-glutamic acid, 86.4 percent) and lowest for the basic ones (L-arginine, 37.4 percent and L-lysine, 31.4 percent). Stereospecificity for glucose and alanine uptake, saturation kinetics for glutamic acid (Km equal to 4.8 mM) and aspartic acid (Km equal to 2.7 mM), and cross-inhibition among uptake of the acidic amino acids were observed. These findings confirmed the applicability of a technique which was originally developed for studies of amino acid uptake in brain to characterization of transport systems in liver.

[1]  J. Exton,et al.  Effects of glucagon on amino acid transport and utilization in the perfused rat liver. , 1969, The Journal of biological chemistry.

[2]  W. Oldendorf Stereospecificity of blood-brain barrier permeability to amino acids. , 1973, The American journal of physiology.

[3]  P. Lefevre Rate and affinity in human red blood cell sugar transport. , 1962, The American journal of physiology.

[4]  C Crone,et al.  Facilitated transfer of glucose from blood into brain tissue. , 1965, The Journal of physiology.

[5]  C. Tidball INTESTINAL AND HEPATIC TRANSPORT OF CHOLATE AND ORGANIC DYES. , 1964, The American journal of physiology.

[6]  J. Crawhall,et al.  Transport of some amino acids and sugars in rat-liver slices. , 1968, Biochimica et biophysica acta.

[7]  L. Jefferson,et al.  Growth hormone stimulation of amino acid transport and utilization by the perfused rat liver. , 1975, The Journal of biological chemistry.

[8]  G. Cahill,et al.  Glucose penetration into liver. , 1958, The American journal of physiology.

[9]  Lassen Na Capillary diffusion capacity of sodium studied by the clearances of Na-24 and Xe-133 from hyperemic skeletal muscle in man. , 1967 .

[10]  C. Park,et al.  Stereospecific transport of glucose in the perfused rat liver. , 1968, The American journal of physiology.

[11]  H. Christensen Some special kinetic problems of transport. , 1969, Advances in enzymology and related areas of molecular biology.

[12]  P. Lund Control of glutamine synthesis in rat liver. , 1971, The Biochemical journal.

[13]  W H Oldendorf,et al.  Brain uptake of radiolabeled amino acids, amines, and hexoses after arterial injection. , 1971, The American journal of physiology.

[14]  D. Yudilevich,et al.  Liver distribution and uptake of molecules studied by rapid indicator-dilution technique. , 1971, The American journal of physiology.

[15]  J. Sipe,et al.  Mediated transport of glucose between blood and brain in the cat. , 1971, The American journal of physiology.

[16]  W H Oldendorf,et al.  Kinetics of blood-brain transport of hexoses. , 1975, Biochimica et biophysica acta.

[17]  J. E. Richmond,et al.  Uptake and metabolism of amino acids by the dog liver perfused in situ , 1962 .

[18]  W H Oldendorf,et al.  Carrier-mediated blood-brain barrier transport of short-chain monocarboxylic organic acids. , 1973, The American journal of physiology.

[19]  H. Krebs,et al.  Restricted permeability of rat liver for glutamate and succinate. , 1968, The Biochemical journal.

[20]  W. Schenk,et al.  Interaction between portal venous and hepatic arterial blood flow: an experimental study in the dog. , 1972, Surgery.

[21]  A. Harper,et al.  Transport of nonmetabolizable amino acids in rat liver slices. , 1969, Biochimica et biophysica acta.

[22]  S. Adibi Interrelationships between level of amino acids in plasma and tissues during starvation. , 1971, The American journal of physiology.

[23]  D. Yudilevich,et al.  Facilitated transport of amino acids through the blood-brain barrier of the dog studied in a single capillary circulation. , 1972, Brain research.

[24]  H. Christensen On the development of amino acid transport systems. , 1973, Federation proceedings.

[25]  E. Forker Hepatocellular uptake of inulin, sucrose, and mannitol in rats. , 1970, The American journal of physiology.

[26]  W. Lacy Uptake of individual amino acids by perfused rat liver: effect of acute uremia. , 1970, The American journal of physiology.

[27]  W. Schenk,et al.  The effect of glucagon on hepatic blood flow. An experimental study in the dog. , 1970, Archives of surgery.