51
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Krooth RS, May SR, Stern HJ. A theory for the chemical mediation of the excitability of the brain, with special reference to natural and drug-induced sleep. J Theor Biol 1977; 66:595-652. [PMID: 196142 DOI: 10.1016/0022-5193(77)90235-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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52
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Dantzler WH, Silbernagl S. Renal tubular reabsorption of taurine, gamma-aminobutyric acid (GABA) and beta-alanine studied by continuous microperfusion. Pflugers Arch 1976; 367:123-8. [PMID: 1034908 DOI: 10.1007/bf00585147] [Citation(s) in RCA: 45] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Renal tubular reabsorption of taurine, gamma-aminobutyric acid (GABA), and beta-alanine was studied in vivo et situ by continuous microperfusion of single proximal tubules of the rat. In each case, reabsorption was much slower than that for other amino acids that have been studied. With a concentration of 0.1 mmol/l in initial load was reabsorbed over perfusion distance of 3 mm. Taurine reabsorption saturated with only 2.17 mmol/l in initial perfusate. Assuming simple two-parameter kinetics, upper limits for Km of 0.54 mmol/l and forVmax of 0.59 pmol-cm-1--s-1 for tubular reabsorption of taurine were estimated. High (20 mmol/l) concentrations of taurine or beta-alanine in perfusate completely inhibited GABA reabsorption, but L-phenylalanine (20 mmol/l) had no significant effect. The results indicate that the three amino acids are reabsorbed slowly from the proximal tubule by what may be a common transport system. This system appears to have a high affinity but low capacity and to be different from other known renal tubular transport systems for amino acids.
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53
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Scriver CR, Chesney RW, McInnes RR. Genetic aspects of renal tubular transport: diversity and topology of carriers. Kidney Int 1976; 9:149-71. [PMID: 940260 DOI: 10.1038/ki.1976.18] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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54
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Sabater J, Ferré C, Puliol M, Maya A. Histidinuria: a renal and intestinal histidine transport deficiency found in two mentally retarded children. Clin Genet 1976; 9:117-24. [PMID: 1248169 DOI: 10.1111/j.1399-0004.1976.tb01556.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Two siblings presenting slight mental retardation showed an abnormal elimination of histidine, their blood levels for the same amino acid being normal. The percentage of tubular resorption of histidine was calculated in both boys, and the values were 40.1 per cent (case 1) and 52.8 per cent (case 2). All other amino acids essayed were normal. After an oral overload test with histidine, a low intestinal absorption was found in the two boys, the values of this test in the parents being intermediate between those of the children and of the three normal controls and corresponding to heterozygosity. In view of the studies carried out on the two boys, it is possible to conclude that they are suffering from an impairment in their histidine membrane transport system which affects the kidney and intestines. Since they are siblings a genetically determined trait may be suspected.
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55
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Chesney RW, Scriver CR, Mohyuddin F. Localization of the membrane defect in transepithelial transport of taurine by parallel studies in vivo and in vitro in hypertaurinuric mice. J Clin Invest 1976; 57:183-93. [PMID: 1245598 PMCID: PMC436638 DOI: 10.1172/jci108258] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We investigated the mechanism of taurinuria in three inbred strains of mice: A/J, a normal taurine excretor (taut+); and two hypertaurinuric (taut-) strains, C57BL/6J and PRO/Re. Plasma taurine is comparable in the three strains (approximately 0.5 mM), but taurinuria is 10-fold greater in taut- animals. Fractional reabsorption of taurine is 0.967 +/- 0.013 (mean +/- SD) in A/J); and 0.839 +/- 0.08 and 0.787 +/- 0.05 in C57BL/6J and PRO/Re, respectively. Taurine concentration in renal cortex intracellular fluid (free of urine contamination) is similar in the three strains. Taurine reabsorption is inhibited by beta-alanine, in taut+ and taut- strains. These in vivo findings reveal residual taurine transport activity in the taut- phenotype and no evidence for impaired efflux at basilar membranes as the cause of impaired taurine reabsorption. Cortex slices provide information about uptake of amino acids at the antiluminal membrane. Taurine behaves as an inert metabolite in mouse kidney cortex slices. Taurine uptake by slices is active and, at less than 1 mM, is greater than normal in taut- slices. Concentration-dependent uptake studies reveal more than one taurine carrier in taut+ and taut- strains. The apparent Km values for uptake below 1 mM are different in taut- and taut+ slices (approximately 0.2 mM and approximately 0.7 mM, respectively); the apparent Km values above 1 mM taurine are similar in taut+ and taut- slices. Efflux from slices in all strains in the same (0.0105-0.0113 mumol-min-1-g-1 wet wt), but taut- tissue retains about 10% more radioactivity over the period of efflux. beta-Alanine is actively metabolized in mouse kidney. Its uptake in the presence of blocked transamination, is greater; its intracellular oxidation is attenuated; and its exchange with intracellular taurine is diminished in taut- slices. These findings indicate impaired beta-amino acid permeation on a low-Km uptake system at the luminal membrane in the taut- phenotype. beta-Amino acids are not reclaimed efficiently either from the innermost luminal pool in cortex slices or from the ultrafiltrate in the tubule lumen in vivo. The former leads to high uptake ratios in vitro, the latter to high clearance rates in vivo. In vitro and in vivo data are thus concordant. This is the first time that a hereditary defect in amino acid transport has been assigned to a specific membrane surface in mammalian kidney.
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56
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Abstract
Carnosinase, the dipeptidase which hydrolyses carnosine and other histidine-containing dipeptides, was assayed in mucosal tissues of the human and of the rat gut. Kinetic properties of the intestinal enzyme were found to be similar to carnosinase of other animal tissues. Little or no activity was detected in human gastric or colonic mucosa, and the levels were lower in duodenal than jejunal mucosa. The distribution of carnosinase is similar to that of the disaccharidases. Mean carnosinase activity was 8-8 units/g weight in 15 patients with histologically normal mucosa compared with 5-7 units in five with villous atrophy. The enzyme levels increased with histological improvement of the mucosa in patients with coeliac disease on a gluten-free diet. Tolerance curves for carnosine and its constitutent amino acids showed malabsorption of the dipeptide in a patient with carnosinase deficiency. It is concluded that the intestinal mucosa has much less hydrolase activity for carnosine than for glycylglycine and other dipeptidases, and the relatively slow hydrolysis appears to be the rate-limiting step in the total absorptive process.
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57
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Monaco F, Mutani R, Durelli L, Delsedime M. Free amino acids in serum of patients with epilepsy: significant increase in taurine. Epilepsia 1975; 16:245-9. [PMID: 1149711 DOI: 10.1111/j.1528-1157.1975.tb06054.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
More than half the amino acids determined in serum were lower in patients with epilepsy than in control subjects. Taurine was the only amino acid to be increased in epilepsy. The changes could represent a compensatory metabolic reaction to limit the imbalance of amino acids in epileptic brain and to facilitate uptake of taurine, which has an anticonvulsant action.
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58
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59
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Enwonwu CO, Worthington BS. Accumulation of histidine, 3-methylhistidine, and homocarnosine in the brains of protein-calorie deficient monkeys. J Neurochem 1973; 21:799-807. [PMID: 4201946 DOI: 10.1111/j.1471-4159.1973.tb07524.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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60
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Slavik M, Lovenberg W, Keiser HR. Changes in serum and urine amino acids in patients with progressive systemic sclerosis treated with 6-azauridine triacetate. Biochem Pharmacol 1973; 22:1295-300. [PMID: 4727783 DOI: 10.1016/0006-2952(73)90303-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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61
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62
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63
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Slavik M, Keiser HR, Lovenberg W, Sjoerdsma A. Hyperaminoacidemia in rabbits treated with 6-azauridine triacetate. LIFE SCIENCES. PT. 2: BIOCHEMISTRY, GENERAL AND MOLECULAR BIOLOGY 1971; 10:1293-5. [PMID: 5144389 DOI: 10.1016/0024-3205(71)90236-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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64
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65
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Saifer A. Rapid screening methods for the detection of inherited and acquired aminoacidopathies. Adv Clin Chem 1971; 14:145-218. [PMID: 4109903 DOI: 10.1016/s0065-2423(08)60146-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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66
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Stewart GG, Abbs ET, Roberts DJ. Biochemical effects of fluoroacetate administration in rat brain, heart and blood. Biochem Pharmacol 1970; 19:1861-6. [PMID: 5513968 DOI: 10.1016/0006-2952(70)90284-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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67
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Abstract
A severely affected case of Hartnup disease is reported, where the patient responded rapidly to nicotinamide. This supports the view that all the clinical features, except reduced stature from general nutritional defect, are secondary to tryptophan and nicotinamide deficiency rather than to an unknown toxic factor. Severe malabsorption of both tryptophan and phenylalanine was demonstrated. The dipeptide carnosine was absorbed normally whereas when the two constituent amino acids, beta-alanine and L-histidine, were ingested, absorption of the former was normal but that of the latter was grossly defective. The suggestion is advanced that in cases of Hartnup disease protein nutrition is maintained by intestinal uptake of amino acids as oligopeptides rather than as free amino acids. By contrast, both modes of absorption are probably important in normal subjects. Radiology of the small intestine is abnormal in Hartnup disease when a large amount of protein is admixed with the barium meal.
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68
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69
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Scriver CR, Hechtman P. Human genetics of membrane transport with emphasis on amino acids. ADVANCES IN HUMAN GENETICS 1970; 1:211-74. [PMID: 4950283 DOI: 10.1007/978-1-4684-0958-1_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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70
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Whelan DT, Scriver CR, Mohyuddin F. Glutamic acid decarboxylase and gamma-aminobutyric acid in mammalian kidney. Nature 1969; 224:916-7. [PMID: 5389396 DOI: 10.1038/224916a0] [Citation(s) in RCA: 52] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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71
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Scriver CR, Whelan DT. Glutamic acid decarboxylase (GAD) in mammalian tissue outside the central nervous system, and its possible relevance to hereditary vitamin B6 dependency with seizures. Ann N Y Acad Sci 1969; 166:83-96. [PMID: 5262035 DOI: 10.1111/j.1749-6632.1969.tb54259.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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72
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Hyánek J, Bremer HJ, Slavik M. 'Homocystinuria' and urinary excretion of beta-amino acids in patients treated with 6-azauridine. Clin Chim Acta 1969; 25:288-90. [PMID: 5801395 DOI: 10.1016/0009-8981(69)90268-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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73
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AMINOACIDS, AMINES, AND RELATED COMPOUNDS. CHROMATOGRAPHY 1969. [DOI: 10.1016/b978-0-433-30503-3.50012-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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74
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75
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76
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Gras G, Tuset N, Caralps A, Gil-Vernet JM, Magriña N, Brulles A, Conde M. Beta-alaninuria following human renal allotransplantation. Clin Chim Acta 1968; 20:295-8. [PMID: 4297716 DOI: 10.1016/0009-8981(68)90163-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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77
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Perry TL, Hansen S, Tischler B, Bunting R, Berry K. Carnosinemia. A new metabolic disorder associated with neurologic disease and mental defect. N Engl J Med 1967; 277:1219-27. [PMID: 6058610 DOI: 10.1056/nejm196712072772302] [Citation(s) in RCA: 83] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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78
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Abstract
A mutation affecting renal transport of proline, hydroxyproline, and glycerine occurs in man. In the presumed homozygote there is still significant residual transport of these compounds; however, this remaining function is saturated at normal concentrations of substrate in the plasma and is not inhibited by L-proline in the expected way. The presumed heterozygote has partial loss of a transport system common to the three substrates, which becomes saturated at high concentrations of substrate and is inhibited by L-proline. Two different types of transport systems are proposed: a common system and systems with lower capacity and greater specificity. The two types of transport appear to be controlled by separate genes.
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79
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Friedlander WJ. Epilepsy. PROGRESS IN NEUROLOGY AND PSYCHIATRY 1967; 22:217-47. [PMID: 4386764 DOI: 10.1016/b978-1-4831-9662-6.50013-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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