Metanephrine

• 5001-33-2
• 5090-31-3 (hydrochloride)
• 881-95-8 (DL- hydrochloride)

• 97-31-4
• 1011-74-1 (hydrochloride)

Attention

Attention

As metanephrines refers to two methylation products of the catecholamines adrenaline, the metanephrine and norepinephrine, the normetanephrine. Both substances arising from their predecessors by the action of the enzyme catechol-O- methyltransferase ( COMT), the configuration is retained. You are excreted in part directly as conjugates in the urine, and the other part by means of the enzyme monoamine oxidase (MAO ) further deaminated to 3-methoxy -4- hydroxymandelsäurealdehyd, which is then oxidized in a further step, either to VMA (VMS ) or 3 - methoxy-4- hydroxyphenylglycol ( MHPG, MOPEG ) is reduced, which will then also be excreted in the urine.

Effect

Metanephrines are the direct inactive metabolite of epinephrine and norepinephrine, respectively, and have no hormonal effect more.

Significance as a tumor marker

A pathologically elevated levels of metanephrines may indicate among other things, a pheochromocytoma, but can also be caused by stress. Metanephrines are determined at a suspected adrenaline or noradrenaline producing tumor, which can be done as well as the direct determination of catecholamines or (formerly ) of the VMA for the diagnosis here.

Determination in urine or blood plasma

For the determination of metanephrines in the urine, the patient collects his urine for a day ( 24-hour urine collection ) in a collection vessel provided with hydrochloric acid. The actual determination is then carried out by means of high performance liquid chromatography (HPLC) or direct chemical detection methods. New methods of determination work directly with blood plasma, and thus circumvent the cumbersome and error-prone collecting the urine.