Plasma Metanephrines Are Markers of Pheochromocytoma Produced by Catechol-O-Methyltransferase Within Tumors

Plasma Free Metanephrines as Diagnostic Markers of Pheochromocytoma

Quantitative determination of catecholamines and their O-methyl metabolites plays an important role in the diagnosis of pheochromocytoma (PHEO) – adrenal medulla tumour. This kind of tumour synthesizes, stocks, metabolizes and mostly secretes catecholamines. For this reason it is possible to use elevated concentrations of catecholamines and their metabolic products from plasma and urine as diag...

Plasma Metanephrines in the Diagnosis of Pheochromocytoma

Plasma metanephrines in the diagnosis of pheochromocytoma.

OBJECTIVE To examine whether tests for plasma metanephrines, the o-methylated metabolites of catecholamines, offer advantages for diagnosis of a pheochromocytoma over standard tests for plasma catecholamines or urinary metanephrines. DESIGN Cross-sectional study. SETTING 3 clinical specialist centers. PATIENTS 52 patients with a pheochromocytoma; 67 normotensive persons and 51 patients wi...

Metabolism of catechol estrogens by erythrocyte catechol-O methyltransferase.

Fishman and Tulchinsky (1) present evidence that the catechol estrogen 2hydroxyestrone suppresses serum prolactin in normal ovulatory young women. However, in 3 of the 12 subjects studied the authors were unable to suppress serum prolactin and suggested that prolactin response to 2-hydroxyestrone is subjectand not time-dependent. In a study designed to evaluate the kinetics of catechol estrogen...

COMT Val158Met Genotype Determines the Direction of Cognitive Effects Produced by Catechol-O-Methyltransferase Inhibition

BACKGROUND Catechol-O-methyltransferase (COMT) metabolizes dopamine. The COMT Val(158)Met polymorphism influences its activity, and multiple neural correlates of this genotype on dopaminergic phenotypes, especially working memory, have been reported. COMT activity can also be regulated pharmacologically by COMT inhibitors. The inverted-U relationship between cortical dopamine signaling and work...