Isolation of <i>iso</i>xanthopterin from human urine

Blair, J. Anthony

doi:10.1042/bj0680385a

Cited by 25 publications

(8 citation statements)

References 13 publications

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“…Both biopterin and neopterin have been isolated from human urine (5)(6)(7). Biopterin in urine probably results from the metabolism of tetrahydrobiopterin (BH4)' BH4 is oxidised to quininoid dihydrobiopterin and converted to 7,8-dihydrobiopterin before being excreted.…”

Section: Introductionmentioning

confidence: 99%

The Levels of Neopterin, Biopterin and the Neopterin/Biopterin Ratio in Urine from Control Subjects and Patients with Alzheimer's Disease and Down's Syndrome

Blair¹,

Winsper²,

Cattell³

et al. 1995

Pteridines

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SummaryThe levels of neopterin, biopterin and the neopterin/biopterin ratio (NIB) were measured in urine samples taken from normal young and elderly control subjects, exceptionally healthy elderly control subjects classified according to the 'Senieur' protocol and patients with Down t s syndrome ( DS ) or Alzheimer's disease (AD). The NIB ratio was approximately unity in the control groups with the exception of the normal elderly controls. The levels of neopterin and biopterin declined with age in the exceptionally healthy 'Senieur' control group. The NIB ratio was elevated in young and old DS patients as a result of a significant increase in neopterin. Neopterin levels were significantly elevated in AD patients compared with the healthy elderly controls, but this did not result in a significant increase in the NIB ratio in these patients. The NIB ratio increased with age in AD patients as a result of a decline in biopterin. These results suggested that there is a cellular immune response in DS and AD patients which in DS, may precede the formation of J3-amyloid deposits in the brain. In addition, there may be a deficiency in tetrahydrobiopterin biosynthesis in AD which becomes more marked with age .

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Section: Introductionmentioning

confidence: 99%

The Levels of Neopterin, Biopterin and the Neopterin/Biopterin Ratio in Urine from Control Subjects and Patients with Alzheimer's Disease and Down's Syndrome

Blair¹,

Winsper²,

Cattell³

et al. 1995

Pteridines

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“…s7 The fate of the pteridine moiety has not been established with certainty, although it has been suggested that a portion of it appears in the urine as isoxanthopterin. 12 Exogenous fowte. Tracer doses of labeled folate administered orally or intravenously are converted to the reduced forms and thence to the cleavage products, and are excreted as such.…”

Section: Number'3mentioning

confidence: 99%

Folates and megaloblastic anemia: A review

Johns

Bertino

1965

Clin Pharma and Therapeutics

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“…Of these reports only a few are concerned with the non-microbiological identification of pteridines and folates. These reports include the isolation of uropterin (later idetitified as xanthopterin) (Koschara & Hrubesch, 1939), isoxanthopterin (Blair, 1958), biopterin Patterson, Broquist, Albrecht, Saltza & Stokstad, 1955;Patterson, Saltza & Stokstad, 1956), neopterin (Sakurai & Goto, 1967), PteGlu* (Baker et al 1965;Anderson, Belcher, Chanarin & Mollin, 1960) and 5,10-CH=H4PteGlu (Silverman, Ebaugh & Gardiner, 1956;Albrecht & Broquist, 1956).…”

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confidence: 99%

The urinary excretion of orally administered pteroyl-l-glutamic acid by the rat

Blair

Dransfield

1971

Biochemical Journal

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1. The urinary excretion of folates after oral administration of [2-(14)C]pteroyl-l-glutamic acid was studied by assaying the radioactivity in the urine and in materials purified and characterized by t.l.c. 2. Radioactivity excreted was 6.8, 5.9 and 30.7% of the oral dose in the first 24h after doses of 3.1, 32 and 320mug/kg respectively. 3. Extensive decomposition of urinary folates to pteroyl-l-glutamic acid was prevented by antioxidants or collection of urine frozen. 4. At the three dosages, two major and one minor radioactive compounds were isolated. One of the major metabolites was 5-methyltetrahydropteroylglutamic acid. The others were unidentified but were not pteroylglutamic acid, 7,8-dihydro-, 5,6,7,8-tetrahydro-, 5- or 10-formyl-tetrahydro-, 5,10-methylidyne-tetrahydro-, 5-formimidoyl-tetrahydro-, 5,10-methylene-tetrahydro-, 5-methyltetrahydro-pteroylglutamic acid, nor any decomposition products of these compounds formed during isolation. Labelled unconjugated pteridines were absent. 5. Labelled pteroyl-l-glutamic acid was displaced by oral administration of unlabelled pteroyl-l-glutamic acid (1.6mg/kg) when given 3.5h after, but not when given 24h after the labelled dose. 6. The results show that orally administered [2-(14)C]pteroyl-l-glutamic acid is absorbed without metabolism and is then metabolized into naturally occurring tetrahydro-folates. 7. These findings are discussed with reference to previous work.

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Isolation of isoxanthopterin from human urine

Cited by 25 publications

References 13 publications

The Levels of Neopterin, Biopterin and the Neopterin/Biopterin Ratio in Urine from Control Subjects and Patients with Alzheimer's Disease and Down's Syndrome

The Levels of Neopterin, Biopterin and the Neopterin/Biopterin Ratio in Urine from Control Subjects and Patients with Alzheimer's Disease and Down's Syndrome

Folates and megaloblastic anemia: A review

The urinary excretion of orally administered pteroyl-l-glutamic acid by the rat

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