A comparative study of the binding of l-tryptophan and bilirubin by plasma proteins

Fellows, Florence C. I.; Hird, F. J. R.

doi:10.1016/0003-9861(82)90192-8

Cited by 14 publications

(5 citation statements)

References 24 publications

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“…The experimental conditions may have had an influence on the disparate conclusions, because Pardridge (1979) used a lower (20 p M ) total tryptophan concentration, whereas higher concentrations (69 and 88 p M ) were used by Bloxam et al (1980). The concentration used in the present work was 72 pM (a physiological concentration; Fellows and Hird, 1982), and we found for L-tryptophan that at lower albumin concentrations (<2 g/ 100 ml) a decrease in unbound fraction did produce a substantial decrease in brain uptake (Fig. 3).…”

Section: Discussionmentioning

confidence: 94%

Brain Uptake of L‐Tryptophan and Diazepam: The Role of Plasma Protein Binding

Fenerty

Lindup

1989

Journal of Neurochemistry

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The brain uptake index (BUI) of L-tryptophan and diazepam into the right and left hemispheres and the cerebellum has been measured after a bolus injection into the carotid artery of the anaesthetised rat. The effect of a range of albumin concentrations (38 microM to 1.4 mM; 0.25-9 g/100 ml) on the viscosity and osmotic pressure of the bolus was studied as a preliminary to the brain uptake experiments. Dextran (Mr 60,000-90,000) was included in the injection to ensure constant viscosity and osmotic pressure. An increase in albumin concentration up to 2 g/100 ml substantially reduced the BUI of L-tryptophan, but a further increase in albumin concentration up to 9 g/100 ml resulted in only a slow fall in the BUI of L-tryptophan which was not proportional to the larger fall in the concentration of unbound L-tryptophan. Furthermore, the use of norharmane as an inhibitor of L-tryptophan binding did not reveal a simple relationship between its unbound concentration and BUI. A decrease in the unbound concentration of diazepam also reduced its BUI, but again there was no straightforward relationship between this and unbound diazepam concentration. The differences observed in the BUI of inulin from solutions of either dextran or albumin indicate not only that each macromolecule may exert particular effects on the BUI, perhaps by an influence on cerebral blood flow, but also show how difficult it is to devise solutions for injection which differ in respect of only one variable, that of the unbound ligand concentration.

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Section: Discussionmentioning

confidence: 94%

Brain Uptake of L‐Tryptophan and Diazepam: The Role of Plasma Protein Binding

Fenerty

Lindup

1989

Journal of Neurochemistry

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“…Albumin-like proteins were reported in lampreys on the basis of electrophoresis but these proteins did not bind fatty acids [12]. Studies on the serum proteins of rainbow trout have given conflicting views [5,6] but it has been proposed that the term para-albumin be given to the second and third most anodally migrating proteins based on their low molecular masses, lack of carbohydrate staining, solubility in ammonium sulphate, and electrophoretic mobilities [6].…”

Section: Discussionmentioning

confidence: 99%

Palmitate‐binding, serum albumin‐like proteins in salmonids

Davidson

Birt

et al. 1988

FEBS Letters

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There has been considerable controversy over the existence of serum albumin in fish. One of the physiological functions of albumin is to bind free fatty acids. This characteristic was used to screen the plasma of seven species of salmonids. Each species contains a protein fraction that (i) binds palmitate, (ii) has a molecular mass similar to that of human serum albumin, and (iii) is one of the most rapidly migrating proteins when salmonid plasma is subjected to anodal polyacrylamide gel electrophoresis.We conclude therefore, that salmonids have serum albumins that are homologous to the serum albumin of higher vertebrates.

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“…The binding of plasma tryptophan to albumin is known to be affected by bilirubin, which displaces TRP from binding sites (Fellows and Hird 1982); and increased levels of free TRP have been observed in the plasma of jaundiced subjects (Young et al 1975, Zoli et al 1981. While no relationship was seen between CSF TRP'and plasma bilirubin in our normal group, a strong relationship was observed in the complicated group (r 0.73, p<O*OOl).…”

Section: Correlation Studiesmentioning

confidence: 99%

NEUROTRANSMITTER PRECURSORS and METABOLITES IN CSF OF HUMAN NEONATES

Anderson

Hoder

Shaywitz

et al. 1985

Develop Med Child Neuro

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SUMMARY The amino‐acid precursors tryptophan and tyrosine, and the major metabolites 5‐hydroxyindoleacetic acid, indoleacetic acid, homovanillic acid and 3‐methoxy‐4‐hydroxyphenethyleneglycol, related to the central neurotransmitters serotonin, dopamine and norepinephrine, were measured in 62 samples of cerebrospinal fluid from human neonates. Means are reported for the samples from 17 medically uncomplicated infants and for the larger group (42 to 45) of infants with medical complications. The latter group was divided according to diagnosis and medication. All groups had significantly higher levels of all compounds in comparison with older children and adults. There were few significant subgroup differences in the group with complications. In both the normal and complicated groups a number of significant correlations were observed between the compounds themselves and with other physiological measures. RÉSUMÉ Précurseurs de neurotransmetteurs el métabolites dons le LCR des nouveau‐nés humains Les acides aminés précurseurs, tryptophane et tyrosine, et les métabolites majeurs acide 5‐hydroxyindolacétique, acide indolacétique, acide homovanillique et 3‐methoxy‐4‐hydroxyphenethyleneglycol, reliés aux neurotransmetteurs centraux, sérotonine, dopamine et norepinéphrine ont été mesurés dans 62 échantillons de LCR de nouveau‐nés humains. Les moyennes des échantillons de 17 nourrissons médicalement sans complication et du plus large groupe (42 à 45) de nourrissons avec complications médicales sont donnèes. Le dernier groupe a été divisé en fonction du diagnostic et de la médication. Tous les groupes avaient des taux significativement plus eleves de tous les composes en comparaison avec des enfants plus âgés et des adultes. Il y avait peu de differences significatives entre sous‐groupes dans le groupe avec complications. A la fois dans les groupes normal et compliqué, plusieurs corrélations significatives ont été observées entre les taux de composés et d'autres mesures physiologiques. ZUSAMMENFASSUNG Vorstufen und Metabolite von Neurotransmittern im Liquor von Neugeborenen Die Aminosäuren Tryptophan und Tyrosin und die wichtigsten Metabolite 5 Hydroxyindolessigsäure, Indolessigsäure, Homovanillinsäure und 3‐Methoxy‐4‐hydroxyphenethylenglycol sind Vorstufen der zentralen Neurotransmitter Serotonin, Dopamin un Norepinephrin; diese Substanzen wurden in 62 Liquorproben von Neugeborenen gemessen. Es werden die Mittelwerte für die 17 klinisch gesunden Kinder und für die großere Gruppe (42 bis 45) der Kinder mit Komplikationen angegeben. Alle Gruppen hatten signifikant höhere Spiegel für alle Substanzen im Vergleich zu älteren Kindern und Erwachsenen. Bei den Kindern mit Komplikationen fanden sich einige signifikante Unterschiede in Untergruppen. In beiden Gruppen wurden mehrere signifikante Korrelationen zwischen den Substanzen untereinander und mit anderen physiologischen Paramétérn beobachtet. RÉSUMÉN Precursores neurotransmisores y melabolitos en el LCR de recién nacidos humanos Se midieron en 62 muestras de LCR de recien na...

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A comparative study of the binding of l-tryptophan and bilirubin by plasma proteins

Cited by 14 publications

References 24 publications

Brain Uptake of L‐Tryptophan and Diazepam: The Role of Plasma Protein Binding

Brain Uptake of L‐Tryptophan and Diazepam: The Role of Plasma Protein Binding

Palmitate‐binding, serum albumin‐like proteins in salmonids

NEUROTRANSMITTER PRECURSORS and METABOLITES IN CSF OF HUMAN NEONATES

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