Xanthurenic Acid Abstracts 3

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Improvement of oral glucose tolerance in gestational diabetes by pyridoxine.
            (Bennink and Schreurs, 1975) Download
Fourteen pregnant women were shown by the oral glucose tolerance test to have gestational diabetes. In 13 an increased urinary xanthurenic-acid excretion after an oral load of L-tryptophan indicated a relative pyridoxine deficiency. All patients were treated with vitamin B6 (pyridoxine) 100 mg/day for 14 days by mouth, after which the pyridoxine deficiency disappeared and the oral glucose tolerance improved considerably. Only two patients then had sufficiently impaired glucose tolerance to justify the diagnosis of gestational diabetes; Our results substantiated our hypothesis that increased xanthurenic-acid synthesis during pregnancy may cause gestational diabetes. Treatment with vitamin B6 makes the production of xanthurenic-acid normal by restoring tryptophan metabolism and improves the oral glucose tolerance in patients with gestational diabetes.

The Effect Of Vitamin Supplementation On The Urinary Excretion Of Tryptophan Metabolites By Pregnant Women.
            (Brown et al., 1961) Download
The excretion of the tryptophan metabolites -  kynurenine, kynurenic acid, acetylkynurenine, hydroxykynurenine, xanthurenicacid,o-aminohippuric acid and N-methyl-2-pyridone-5-carboxa- mide-was measured quantitatively in the urine of non pregnant women, pregnant women without and with vitamin supplementation, and in the same subjects postpartum. Pyridone excretion remained high even after pyridoxine supplementation had significantly lowered the excretion of xanthurenic acid, hydroxykynurenine and kynurenine. Administration of vitamins other than pyridoxine had no detectable effect on excretion of metabolites.

Studies on the xanthurenic acid-insulin complex. II. Physiological activities.
            (Kotake et al., 1968) Download
The activity of xanthurenic acid-insulin complex on the blood sugar levels of rabbits is about 50% of that of native insulin. Formation of the complex also decreased the activities of insulin on the uptake of glucose by epididymal fat pads and by isolated diaphragms of rats.


 

Excretion of xanthurenic acid in urine from patients with diabetes mellitus
            (Kotake and Hattori, 1979) Download
In cases of mild or middle grade diabetics, only 30-50% of the patients excreted XA in their urine, but if they were loaded with tryptophan the ratio would increase. We believe that there are some diabetics whose tryptophan metabolism is distorted, since their excretion rate of XA in urine is much higher than that of healthy individuals. Whether these diabetic patients have a shortage of vitamin B6 or there is a decrease in the change of vitamin B6 to the active form, pyridoxal phosphate, is discussed.

Studies on the xanthurenic acid-insulin complex. 3. Distribution of xanthurenic acid and formation of xanthurenic acid-insulin complex in serum.
            (Murakami and Kotake, 1972) Download
The amounts of XA bound to the serum protein are larger in a normal serum than a diabetic serum. The distribution of 131I-insulin in the serum was also studied. To elucidate the binding of XA to insulin, tritium labeled XA was injected to the rat and the sera were subjected to chromatography on the Sephadex column after it was treated with anti-insulin serum. The distribution of 3H-XA was checked in eluates. The result shows that injected 3H-XA binds to the circulating insulin and the resulting complex combines to the anti-insulin serum. Thus, we can confirm the binding ' of XA with insulin in the serum.

Metabolism of tryptophan in diabetes mellitus.
            (Oka and Leppanen, 1963) Download
The metabolism of tryptophan was studied in 10 patients with diabetes mellitus and 12 control subjects by deter- mining the urinary excretion of 5-hydroxyindoleacetic acid, kynurenine, anthranilic acid, 3-hydroxyanthranilic acid and xanthurenic acid before and after a loading dose of 2 g of L-tryptophan. A disorder of tryptophan metabolism was observed. This appeared as a markedly increased excretion of xanthurenic acid both before and after the loading dose of L-tryptophan. The excretion of kynurenine was diminished compared to normal and that of 5-hydroxyindoleacetic acid slightly enhanced after the tryptophan load. It is suggested that the metabolic de- rangement observed is at least partially due to a deficiency of vitamin B6.


 

Interaction between xanthurenic acid-insulin complex and zinc ions.
            (Ueda et al., 1977) Download
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.

Detection of vitamin B6 deficiency; utilization of an improved method for rapid determination of xanthurenic acid in urine.
            (Wachstein and Gudaitis, 1952) Download
A modification of the rapid assay method for xanthurenic acid in urine as proposed by Rosen, Lowy and Sprince is presented. It makes use of the excellent buffering capacity of tris (hydroxymethyl) aminomethane and of a precalibrated curve for its colorimetric quantitative determinations. The quantitative estimation of the excreted XA in the urine following a test dose of 10 Gm. dl-tryptophan is a simple procedure for the detection of a vitamin-Be deficiency.

 


References

Bennink, HJ and WH Schreurs (1975), ‘Improvement of oral glucose tolerance in gestational diabetes by pyridoxine.’, Br Med J, 3 (5974), 13-15. PubMed: 1131652
Brown, RR, MJ Thornton, and JM Price (1961), ‘The Effect Of Vitamin Supplementation On The Urinary Excretion Of Tryptophan Metabolites By Pregnant Women.’, J Clin Invest, 40 (4), 617-23. PubMed: 16695856
Kotake, Y, et al. (1968), ‘Studies on the xanthurenic acid-insulin complex. II. Physiological activities.’, J Biochem, 63 (5), 578-81. PubMed: 5723089
Kotake, Y and M Hattori (1979), ‘[Excretion of xanthurenic acid in urine from patients with diabetes mellitus (author’s transl)].’, Nihon Eiseigaku Zasshi, 34 (3), 474-83. PubMed: 537209
Murakami, E and Y Kotake (1972), ‘Studies on the xanthurenic acid-insulin complex. 3. Distribution of xanthurenic acid and formation of xanthurenic acid-insulin complex in serum.’, J Biochem, 72 (2), 251-59. PubMed: 4644301
Oka, M and VV Leppanen (1963), ‘Metabolism of tryptophan in diabetes mellitus.’, Acta Med Scand, 173 361-64. PubMed: 13939730
Ueda, T, et al. (1977), ‘Interaction between xanthurenic acid-insulin complex and zinc ions.’, J Biochem, 82 (1), 67-72. PubMed: 893387
Wachstein, M and A Gudaitis (1952), ‘Detection of vitamin B6 deficiency; utilization of an improved method for rapid determination of xanthurenic acid in urine.’, Am J Clin Pathol, 22 (7), 652-55. PubMed: 14933348