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At least 19 recordsLinked to original sources
PubMed1990

Biosynthesis of xanthurenic acid 8-O-beta-D-glucoside in Drosophila. Characterization of the xanthurenic acid:UDP-glucosyltransferase activity.

Xanthurenic acid 8-glucoside is a side metabolite of the tryptophan-xanthommatin pathway in Drosophila. From 3-hydroxykynurenine, two biosynthetic pathways can be envisaged, one via xanthurenic acid, and another via 3-O-glucoside of 3-hydroxykynurenine. In this report evidence is presented to show that the synthesis takes place via xanthurenic acid. (a) We have demonstrated that the Drosophila melanogaster vermilion purple mutant (unable to synthesize 3-hydroxykynurenine) synthesizes xanthurenic acid 8-glucoside when fed with xanthurenic acid; and (b) the activities required for its synthesis via xanthurenic acid have been found (3-hydroxykynurenine transaminase and xanthurenic acid:UDP-glucosyltransferase). This is the first time that a UDP-glucosyltransferase activity that utilizes xanthurenic acid has been demonstrated. The enzyme in crude extracts from Drosophila sordidula shows the following characteristics. (a) It has optimal activity at 35 degrees C at pH 7.1 (in buffer Tris-HCl), and in the presence of a divalent cation (Mg2+ or Mn2+); (b) the activity is inhibited by xanthurenic acid (above 1.5 mM), UDP, D-gluconic acid 1,5-lactone, and Triton X-100; (c) it is localized in both the microsomal and the soluble fractions; (d) the specific activity is two times higher in heads than in bodies; and (e) the activity is enhanced in flies fed with phenobarbital.

Animals↗
PubMedDate not supplied

Urinary excretion of xanthurenic acid and zinc in diabetes: (3). Occurrence of xanthurenic acid-Zn2+ complex in urine of diabetic patients and of experimentally-diabetic rats.

The urinary excretion of Xanthurenic acid (XA) and Zn2+ in diabetic patients and experimentally-diabetic rats were examined. A significantly elevated excretion of urinary XA was found in diabetic patients and alloxan- and streptozotocin-induced diabetic rats. A significantly high amount of zinc was also found in the urines of the diabetic patients and of the diabetic rats. Our findings indicate that the XA may be substantially excreted, as its complex with Zn2+, into majority of the elevated XA is excreted as its complex with Zn2+.

Animals↗
PubMed1985

Xanthurenic acid 8-O-beta-D-glucoside, a novel tryptophan metabolite in eye-color mutants of Drosophila melanogaster.

An unknown fluorescent metabolite has been isolated from heads of eye-color mutants of Drosophila melanogaster. Only a few mutations cause it to accumulate, viz. cardinal (cd), dark red brown (drb), Henna-recessive (Hnr), purple (pr), Punch2 (Pu2), Punch-Grape (PuGr), and scarlet (st). After purification by ion-exchange chromatography, the spectroscopic, chemical, and enzymatic analyses revealed that it is a novel quinoline derivative: xanthurenic acid 8-O-beta-D-glucoside. Feeding experiments suggest that this glucoside is synthesized from 3-hydroxykynurenine and that free xanthurenic acid is not a precursor. The results from the analysis for its occurrence in double mutants, together with the fact that xanthurenic acid 8-glucoside share the same precursor as xanthurenic acid and xanthommatin, suggest that xanthurenic acid 8-glucoside formation is closely related to the regulation of the last step in the biosynthesis of xanthommatin.

Animals↗
PubMed1989

Kynurenine metabolism and xanthurenic acid formation in vitamin B6-deficient rat after tryptophan injection.

Normal and vitamin B6-deficient rats received an intraperitoneal injection of 30 mg/100g of body wt, and the contents of metabolites in kidney or plasma and the related enzyme activities in kidney were determined. The contents of kynurenine and 3-hydroxykynurenine in B6-deficient rat plasma and kidney were much higher than those in normal rat. The changes of those contents in plasma were parallel to those in kidney, but not in liver. The contents of kynurenic acid and xanthurenic acid in B6-deficient liver, plasma, and kidney were also much higher than those in normal rats. However, the changes of those contents in plasma were parallel to those in liver, but not in kidney. Xanthurenic acid and kynurenic acid accumulated to a much greater extent in kidney than in plasma and liver. Kidney kynureninase activity was very low, but kynurenine aminotransferase activities were very high. These observations indicated that the production of xanthurenic acid after tryptophan injection was favorable in B6-deficient kidney with respect to enzyme activities and substrate concentrations, and suggested that kidney took up kynurenine or 3-hydroxykynurenine from blood and after conversion of them it excreted xanthurenic or kynurenic acid into urine.

Animals↗
PubMed1989

Monoamineoxidase activity in certain brain regions associated with xanthurenic acid excretion in rats on oral contraceptive steroids.

Monoamineoxidase (MAO) activity in some regions of brain and urinary xanthurenic acid were investigated in female rats administered with oral contraceptive (OC) steroids-ethynyl estradiol (Ees), lynestrenol (Ly) and both in combination (Cm) for 75 days. The MAO activity was reduced significantly in most regions specially in cortex-the extent of reduction being 65 per cent with Ees, 51 per cent with Ly and 69 per cent with Cm treatments. In the hypothalamus, the activity was decreased by 50 per cent with Ees, 38 per cent with Ly and by 40 per cent with Cm treatments. In the corpus striatum the activity was reduced by 14 per cent with Ly treatment, 25 per cent with Cm treatment and in the midbrain by 59 per cent with Ees treatment only. The concentration of xanthurenic acid in urine was higher by 55 per cent with Ees, 109 per cent with Ly and by 120 per cent with Cm treatments. These changes in MAO activity and level of xanthurenic acid excretion indicate the possible alteration in the metabolism of neurotransmitter, associated with prolonged use of OC.

Animals↗
PubMed1976

Effect of varying vitamin B6 intake of early-weaned piglets on urinary xanthurenic and kynurenic acid excretion, serum transaminase activity and urea concentration.

In a bipartite rearing experiment (day 1-24 and 24-45) 72 early-weaned piglets were used to study the effect of varying dietary vitamin B6 contents on renal excretion of xanthurenic and kynurenic acid after a tryptophan load, on urea concentration and activities of two transaminases in serum at the end of each period. The animals, divided into 6 groups, were fed ad libitum a prestarter and a starter in period I and II, respectively, each containing 0.5, 1.2, 2.0, 2.8, 3.5 or 6.6 mg vitamin B6 per kg dry matter. The urinary xanthurenic acid excretion was elevated especially at the vitamin B6 supply of 0.5 ppm and rose severalfold with increasing depletion time (period II). In both periods, the smallest amount was excreted by piglets supplemented with 2.8 ppm. In comparison to groups B (1.2 ppm) and C (2.0 ppm), their average excretion rate was reduced by 29% and 15%, respectively, in period I and by 50% and 22%, respectively, in period II. Analogously to xanthurenic acid, the smallest amount of kynurenic acid was excreted by group D (2.8 ppm). Starting from the lowest vitamin B6 supply, the activity of SGPT showed an almost linear increase in both experimental periods. In contrast, SGOT already reached an upper activity level with the dietary vitamin B6 content of 3.5 and 2.8 ppm at the end of period I and II, respectively. The concentration of serum urea was influenced only by the lowest vitamin B6 supply of 0.5 ppm.

Alanine Transaminase↗
PubMedDate not supplied

[Renal excretion of xanthurenic acid as an index of vitamin B6 allowance in infants].

Renal excretion of xanthurenic acid without any tryptophan load, passage of 4-pyridoxic acid with diurnal urine and its excretion with urine collected during 1 hour in the morning on an empty stomach were investigated in 86 practically healthy infants and in 77 others with acute respiratory viral infections aged from two weeks to one year. Investigations of the tryptophan tolerance in infants yielded negative results, viz. on administering to them of D,L-tryptophan in a load dose the infants started vomiting. Practically healthy infants did not excrete xanthurenic acid, while the renal excretion of 4-pyridoxic acid remained within normal limits. In patients at the height of the disease the passage of 4-pyridoxic acid steeply increased. In 9 of them xanthurenic acid appeared in the diurnal urine. In the quiscent stage of the affection in two infants xanthurenuria continued against the general background of diminished excretion of 4-pyridoxic acid. There is no reason to relate the disclosed xanthurenuria in sick infants with the state of hypovitaminosis in them.

Age Factors↗
PubMed1977

Interaction between xanthurenic acid-insulin complex and zinc ions.

An equimolar mixture of a xanthurenic acid-insulin complex and ZnSO4 was separated into an insulin peak and a peak containing xanthurenic acid (XA) and Zn by Sephadex G-75 column chromatograpy. XA and di-[L-histidino]-zinc (II) readily combined to produce di-[L-histidino]-di-xanthurenato zinc (II) (His2-Zn2+-XA2). By increase in the concentration of Zn2+ ions, XA was removed from di-[L-histidino]-di-xanthurenato zinc (II) (His2-Zn2+-XA2) as XA-Zn2+. The XA-insulin complex showed dcreased relative intensity of fluorescence compared with the Zn-insulin when excited at a wavelength of 284 nm. The difference spectrum between native Zn-insulin and XA-insulin complexes showed a slight red shift. A diffference in the CD spectrum between native Zn-insulin and XA-insulin complexes was observed.

Binding Sites↗
PubMed1975

Development of analytical methods for the detection and determination of kynurenic and xanthurenic acids.

A survey was carried out on the techniques developed by numerous research workers in this important field since Liebig discovered the presence of kynurenic acid in the urine of dogs fed on meat and Musajo that of xanthurenic acid in the urine of rats on a fibrin diet. The survey starts with the old methods of assay by precipitation of kynurenic acid and goes on to include the more recent ones of colorimetric assay of xanthurenic acid with ferrous sulphate or ferric chloride and of kynurenic acid by means of transformation into a chloro-derivative of the type of Besthorn dyes. Chromatographic techniques including paper chromatography, thin-layer chromatography, column chromatography nad gas chromatography, enabled researchers to detect the slightest traces of the two quinolincarbonic acids in the biological fluids together with the other metabolites of tryptophan. Among the techniques adopted for this purpose electrophoresis, automatic analyzers, polarography and, finally, the use of labelled substances, in particular L-tryptophan-3-C14, are included.

Animals↗
PubMed1991

Physiological role of 3-hydroxykynurenine and xanthurenic acid upon crustacean molting.

Studies with crabs (Charybdis japonica) and crayfish (Procambarus clarkii) revealed that the tryptophan metabolites, 3-hydroxy-L-kynurenine (3-OH-K) and xanthurenic acid (XA), common secretory products of the X-organ-sinus gland complex of eyestalks from several decapods, regulated the molting of crustaceans in species-nonspecific fashion. Injection of 3-OH-K to the eyestalk-ablated crayfish delayed the onset of the first molt and lengthened the interval between the first and second molts. These lines of evidence were in accord with previous accounts of the so-called "molt inhibiting hormone" (MIH) effect. Removal of eyestalks caused a change in the conversion capacity of exogenous 3-OH-K to XA in the hemolymph. The peak in transformation capacity was followed by a peak in the titer of 20-hydroxyecdysone or molting hormone. Moreover, the seasonal profiles of the XA and ecdysone titers in Charybdis japonica exhibited a staggered relationship in the tissues tested. The ratio of XA to 3-OH-K, which is expected to indicate the apparent 3-OH-Kase activity, fluctuated seasonally and locally. When the Y-organ with the adhering tissues (Y-organ complex or YOC) was incubated during the period of high XA titer, the YOC produced 100 times more ecdysone than before incubation. It is suggested that ecdysteroidogenesis in situ was suppressed during this period by XA, but incubation of the YOC lead to a dramatic acceleration in ecdysone synthesis by overriding this inhibitory effect. XA profoundly repressed ecdysteroidogenesis in the YOC culture. Thus, XA is the ecdysone biosynthesis inhibitor (EBI) and 3-OH-K the precursor in crustaceans. An interfering effect of XA to a biocatalyst cytochrome P-450 system was postulated for the inhibition mechanism of ecdysteroidogenesis.

Animals↗
PubMed1975

The physiological significance of the xanthurenic acid-insulin comples.

The xanthurenic acid-insulin complex was found to have similar immunological properties to native Zn-insulin. This complex showed less hormonal activity on glucose metabolism in adipose tissue than native An-insulin, but its activity was increased by addition of Zn2+ ions.

Adipose Tissue↗
PubMedDate not supplied

Kynurenic acid and xanthurenic acid excretion after tryptophan loading in actinic reticuloid.

The metabolism of L-tryptophan (TRP) before and after an oral loading dose of 20 mg/kg body weight was studied in three patients with actinic reticuloid (AR) and four healthy male volunteers. The preload mean plasma TRP concentrations and mean 24-hour urinary excretions of TRP in the AR group were significantly lower than in the control group. After oral TRP administration, plasma TRP concentrations increased normally in AR, thereby excluding defective intestinal absorption. The mean preload and postload excretions of kynurenic acid (KA), xanthurenic acid (XA), 5-hydroxyindoleacetic acid (5HIAA), and 3-indoleacetic acid (3IAA) were not significantly different between the two groups. We conclude that KA, which has been shown to have phototoxic properties in vitro, is not altered primarily in AR, and that the reported abnormalities of TRP metabolism are most likely the consequence of the severe photosensitivity in this disorder.

Aged↗
PubMed1975

Purification of xanthurenic acid-insuline complex.

Tritium labeled xanthurenic acid (XA)-insulin complexes A and B were obtained. These were shown to be one component by the disc electrophoresis, and bound XA was not liberated by the electrophoresis from the paper electrophoresis experiment. The result of the gel filtration showed that the molecular weight of the complex A and B was 24,000. But there is still a possibility that complex B might be contaminated with free insulin.

Chemical Phenomena↗
PubMedDate not supplied

The clinical significance of an elevated excretion of xanthurenic acid in psychiatric patients.

This study investigations whether the synthesis of nicotinamide out of L-tryptophan is disordered in depression or in anxiety. To this end the excretion of xanthurenic acid (XA) in 24 hours urine was measured after administration of an oral loading dose of 5 grams L-tryptophan. The subjects were depressive, anxious, and alcoholic patients, while other psychiatric patients, served as control group. Anxiety and not depression is the clinical correlate of an elevated excretion of XA. Liver disorder and vitamin B-6 deficiency have to be excluded. A psychiatric control group is necessary.

Adult↗