Advances in catecholamine and metabolite measurements for diagnosis of pheochromocytoma

Abstract

Assessment of catecholamine production and excretion is important in the laboratory detection of pheochromocytoma, a rare but curable cause of hypertension. Advances in catecholamine and metabolite methodologies have enhanced the diagnostic acumen by increasing analytical sensitivity and eliminating many of the interferences observed with earlier methods. Estimation of urinary catecholamines metanephrine and vanillylmandelic acid is routinely used in the biochemical detection of pheochromocytoma and in monitoring the completeness of tumor excision as well as the possibility of recurrence. Traditional spectrophotometric and fluorometric methods for urinary catecholamines and their metabolites are being replaced by highly sensitive and selective chromatographic methods. The ability to quantify individual catecholamines and metanephrines by high-performance liquid chromatography is of particular value for detecting familial forms of the tumor that may secrete epinephrine. Plasma norepinephrine and epinephrine measurements are of additional diagnostic value in determining recent catecholamine release and response to clonidine suppression. For either urine or plasma measurements, appropriate patient preparation, sample collection, and method validation along with an understanding of the variable pattern of catecholamine secretion and metabolism in pheochromocytoma are essential. Advances in laboratory methodology and reference intervals for catecholamines for clinical interpretation are reviewed.

Alveolar epithelial fluid transport and the resolution of clinically severe hydrostatic pulmonary edema

“…Average interval epinephrine concentrations in the plasma ranged from 99 to 19,170 pg/ml (10 Ϫ12 to 10 Ϫ7 M). Reported maximum plasma epinephrine concentrations in unstressed, supine, normotensive control human subjects are ϳ100-150 pg/ml (51). There were no significant differences in the plasma epinephrine levels in relationship to the rates of alveolar fluid clearance (Fig.…”

Catecholamine biosynthesis and physiological regulation in neuroendocrine cells

“…Sympathoadrenal activity can be assessed by measuring CAs in plasma or by recording impulses in sympathetic nerves to skin and muscles by microneurography (Christensen 1991, Hjemdahl 1993. Numerous methodologies have been published for the assay of CAs in plasma, illustrating the fact that there are many analytical problems (Rosano et al 1991, Hjemdahl 1993. However, when correctly sampled, measured and interpreted, plasma CAs can yield very valuable information on sympathoadrenal activity.…”

Electrochemical Cyclization of Adrenaline, the Simplest Derivatization for its Selective Determination

“…Catecholamines (CAs) are known as one the most important class of neurotransmitters that their levels in blood are associated with psychological reactions. Their similar chemical structures consist an o‐benzenediol (catechol) and an amine side chain makes their selective determination challenging . Various analytical attempts have been devoted for selective determination of catecholamines and successful examples are mostly chromatographic based methods .…”