Urine vanillylmandelic acid

Vanillylmandelic acid human urine acidification, centrifugation ion-pair CIS Affix EC 65... 

Large doses may decrease urinary excretion of phenolsulfonphthalein. Salicylates in the urine result in falsely elevated vanillylmandelic acid (VMA) with most tests, but falsely decrease VMA determinations by the Pisano method. 

Adrenaline is synthesised in the adrenal medulla and at sympathetic nerve endings from phenylalanine and metabolised by oxidation (monoamine oxidase MAO) or conjugation (catechol 0-methyl transferase COMT). It is excreted in the urine as vanillylmandelic acid. Its main physiological effects are at pi and a adrenoceptors, with less marked effects at (P2... 

Magera MJ, Thompson AL, Stoor AL, Helgeson JK, Matern D, Rinaldo P (2003) Determination of vanillylmandelic acid in urine by stable isotope dilution and electrospray tandem mass spectrometry. Clin Chem 49 825-826... 

Degradation of catecholamines The catecholamines are inacti vated by oxidative deamination catalyzed by monoamine oxidase (MAO), and by O-methylation carried out by catechol-O-methyl-transferase (COMT, Figure 21.15). The two reactions can occur in either order. The aldehyde products of the MAO reaction are axi dized to the corresponding acids. The metabolic products of these reactions are excreted in the urine as vanillylmandelic acid, metanephrine, and normetanephrine. 

Potential fates of recaptured norepinephrine Once norepinephrine reenters the cytoplasm of the adrenergic neuron it may be taken up into adrenergic vesicles via the amine transporter system and be sequestered for release by another action potential or persist in a protected pool. Alternatively, norepinephrine can be oxidized by monoamine oxidase (MAO) present in neuronal mitochondria. The inactive products of norepinephrine metabolism are excreted in the urine as vanillylmandelic acid (VMA), metanephrine and normetanephrine. 

Biotransformations Epinephrine, like the other catecholamines, is metabolized by two enzymatic pathways COMT, which has S-adenosylmethionine as a cofactor, and MAO (see Figure 6.3). The final metabolites found in the urine are metanephrine and vanillylmandelic acid. [Note Urine also contains normeta-nephrine, a product of norepinephrine metabolism.]... 

Kahane et al. [169] first oxidized vanillylmandelic acid, after its extraction from urine by the action of sodium periodate, to vanillin. The vanillin was then converted into the methyloxime by reaction with methoxylammonium chloride and finally silylated. The recovery of the total procedure, including extraction from urine, is said to be minimally 95%, with the resulting derivative being highly specific for the compound under analysis. The GC analysis was performed on QF-1 as stationary phase. 

Homovanillic and vanillylmandelic acids, the major metabolites of catecholamines, are often tested in urine for neurological diagnosis and for monitoring the... 

Pheochromocytoma can best be detected by studying the urinary elimination of vanillylmandelic acid. Armstrong et al. (A16) first demonstrated that the elimination of this metabolite of epinephrine and norepinephrine is greatly increased in such patients. The amount found in urine ranges, generally, from 10 to 100 times that of epinephrine and norepinephrine (G13), so that the study of the increase in urinary vanillylmandelic acid appears to be a better way of detecting pheochromocytoma than the study of the increase in the catecholamines themselves. Furthermore, an abnormal elimination of vanillylmandelic acid together with a normal excretion of catecholamines can occur in patients with pheochromocytoma in the normotensive state (K12) this fact shows the superiority of the vanillylmandelic acid determination upon the determination of catecholamines for the detection of these tumors. 

Various techniques, which are rather time consuming for routine use, have been described for the quantitative determination of vanillylmandelic acid in urine (G12). Rapid and more simple techniques, however, allow the semiquantitative estimation of that acid and are especially useful for screening hypertensive subjects for the presence of a pheochromocytoma. Among these rapid techniques, the one which was recently described by Gitlow and Kruk (Gll) allows the use of random urine specimens, whereas the previous ones required that the patient avoid certain foods and drugs prior to the sample collection. 

Thyrotropin-releasing hormone test Thyrotine-binding globulin Thyroxine, free Thyroxine, total Thyroxine index, free Triiodothyronine Urine glucose Vanillylmandelic acid... 

Urine specific gravity Vanillylmandelic acid Waxy casts... 

In patients suspected of having a neoplasm of the adrenal medulla that is secreting excessive quantities of epinephrine or norepinephrine (a pheochromocytoma), either the catecholamines themselves (epinephrine, norepinephrine, and dopamine) or their metabolites (the metanephrines and vanillylmandelic acid, VMA) may be measured in a 24-hour urine collection, or the level of catecholamines in the blood may be measured. A patient who has consistently elevated levels in the blood or urine should be considered to have a pheochromocytoma, particularly if the patient has signs and symptoms of catecholamine excess, such as excessive sweating, palpitations, tremulousness, and hypertension. 

A patient with a tumor of the adrenal medulla experienced palpitations, excessive sweating, and hypertensive headaches. His urine contained increased amounts of vanillylmandelic acid. His symptoms are probably caused by an overproduction of which of the following ... 

Epinephrine is ultimately metabolized by COMT and MAO to 3-methoxy-4-hydroxy-mandelic acid (vanillylmandelic acid), which is excreted as the sulfate or glucuronide in the urine (Fig. 44.5). 

Vanillylmandelic acid (p/Cg 3.42) is a metabolite found in urine, the pH of which is normally In the range from 4.8 to 8.4. Provide the structure of vanillylmandelic acid that you would expect to find in urine with pH 5.8 ... 

Another aspect of catecholaminergic turnover that has been studied is the measurement of the metabolites of dopamine (homovanillic acid, HVA) and noradrenaline (vanillylmandelic acid, VMA). Silbergeld and Chisholm (1976) reported that HVA was increased by 33% in brain and 265% in urine, and VMA was increased by 48% in brain and 216% in urine in mice given 5g Pb/1 (2625 ppm Pb) from birth. It is likely that increased urinary... 

Homovanillic and Vanillylmandelic Acids in Urine from Cases of Neuroblastoma. Reply to Comments Clin. Chem. (Winston-Salem, N. C.) 24 (5) 843 (1978) CA 89 38900u cf. 

Simultaneous Assay by Mass Fragmento-graphy of Vanillylmandelic Acid, Homovanillic Acid, and 3-Methoxy-4-hydroxyphenethylene Glycol in Cerebrospinal Fluid and Urine Biochem. Med. ll(l) 32-40 (1974) CA 82 53621c... 

Determination of Homovanillic and Vanillylmandelic Acids in Urine from Cases of Neuroblastoma. Comments. ... 

Rapid and Simple Gas-Liquid Chromatographic Procedure for Homovanillic and Vanillylmandelic Acids in Urine Clin. Chim. Acta 56(3) 261-264 (1974) CA 82 28048p... 

Determination of Homovanillic, Iso-homovanillic and Vanillylmandelic Acids in Human Urine by Means of Glass Capillary Gas-Liquid Chromatography with Temperature-Programmed Electron-Capture Detection... 

Fig. 2.3. Diagnostic flow-chart in the differentiation of defects of biogenic amine neurotransmitter metabolism. The correct differential diagnosis depends on the pattern of amines and their metabolites in either urine, CSF or plasma. represents increased values, [ represents lowered values. 5HIAA 5-hydroxyindoleacetic acid HVA homovanillic acid 5HT serotonin 30MD 3-0-methyldopa DOPAC dihydroxyphenylacetic acid 3MT 3-methoxytyramine NMN norme-tanephrine VMA vanillylmandelic acid DOPS dihydroxyphenylserine MHPG 3-methoxy-4-hydroxyphenylglycol Y yes N no. Plasma and CSF levels have not been analysed but they probably reflect those seen in urine. For interpretation of quantitative results see pathological values.

Gorden, E.K., Oliver, J., Black, K. and Kopin, I.J. (1974), Simultaneous assay by mass fragmentography of vanillylmandelic acid, homovanillic acid and 3-methoxy-4-hydroxy-phenethylene glycol in cerebrospinal fluid and urine. Biochem. Med., 11,32. 

Garcia, A. Heinanen, M. Jimenez, L.M. Barbas, C. Direct measurement of homovanillic, vanillylmandelic and 5-hydrox3findole acetic acids in urine by capillary electrophoresis. J. Chromatogr. A, 2000, 871, 341-350. Vanholder, R. de Smet, R. Lameire, N. Protein bound uremic solutes the forgotten toxins. Kidney Inter., Suppl. 2001, 78, S266-S270. 

N. is deactivated by O-methylation a monoamine oxidase then removes the NHj group to produce 3-methoxy-4-hydroxymandelic acid (vanillylmandelic parasympathetic nervous function, and is used for the diagnosis of tumors which produce N. or adrenalin. See ascorbate shuttle. 

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