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74

 Functional Assessment of Urinary Neuro-biogenic Amines—A COMPREHENSIVE GUIDE

group on norepinephrine, epinephrine

and their metabolites favors reduction

by aldehyde or aldose reductases. The

deamination of norepinephrine and

epinephrine by monoamine oxidase A

(MAO-A) and the subsequent forma-

tion of VMA have a minimal effect on

catecholamine catabolism in neurons.

Evidence indicates that sulfate-con-

jugated normetanephrine is instead

formed primarily in gastrointestinal tis-

sue. SULT activity has been down-reg-

ulated in vitro by coffee compounds,

green tea polyphenols, quercitin and res-

veratrol. SULT enzymes also conjugate a

variety of xenobiotic chemicals that may

be inhaled or ingested during environ-

mental exposures. SULT1A3 converts

norepinephrine to normetanephrine and

its activity may decrease in liver disease.

In urinary assays, free normeta-

nephrines represent a small proportion

(<3%) of the total measured normeta-

nephrines. Doctor’s Data measures total

normetanephrines, which is the medical

convention.

Consider:

Copper status

( RBC Elements )

Magnesium status

( RBC Elements

)

Status of neurotransmitter precursor

Phenylalanine

( Amino Acids )

Glutathione status

( Glutathione; erythrocytes )

MAOA or COMT SNPs

( DNA Methylation Pathway )

Methionine metabolism and

methylation pathways

( Plasma Methylation Profile, DNA Methylation Pathway )

Oxidative stress/8OH-dG

( DNA Oxidative Damage Assay )

References:

American Association for Clinical Chemistry

(2010)

Urine Metanephrines

http://labtestsonline.org/understanding/ analytes/urine-metanephrine/tab/sample/

accessed 04 Aug 2014

Coughtrie, Michael W. H.; Johnston, Laura

E. (2001)

Interactions between Dietary Chemicals and

Human Sulfotransferases{---}Molecular

Mechanisms and Clinical Significance

Drug Metab. Dispos.

vol. 29 (4) p. 522-528

Daubner, S Colette; Le, Tiffany; Wang,

Shanzhi (2011)

Tyrosine hydroxylase and regulation of dopa-

mine synthesis.

Archives of biochemistry and biophysics

vol.

508 (1) p. 1-12

Eisenhofer, Graeme; Lenders, Jacques W.M.;

Timmers, Henri; Mannelli, Massimo;

Grebe, Stefan K. et al. (2011)

Measurements of Plasma Methoxytyramine,

Normetanephrine, and Metanephrine as

Discriminators of Different Hereditary

Forms of Pheochromocytoma

Clin. Chem.

vol. 57 (3) p. 411-420

Eisenhofer, Graeme; Kopin, Irwin J.;

Goldstein, David S. (2004)

Catecholamine Metabolism: A

Contemporary View with Implications

for Physiology and Medicine

Pharmacol. Rev.

vol. 56 (3) p. 331-349

Eisenhofer, Graeme (2001)

Free or Total Metanephrines for Diagnosis

of Pheochromocytoma: What Is the

Difference?

Clin. Chem.

vol. 47 (6) p. 988-989

Elmasry, A.; Lindberg, E.; Hedner, J.; Janson,

C.; Boman, G. (2002)

Obstructive sleep apnoea and urine cat-

echolamines in hypertensive males: a

population-based study

Eur. Respir. J.

vol. 19 (3) p. 511-517