Catecholamine measurements in clinical medicine

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Abstract
Summary: There are 3 endogenous catecholamines, noradrenaline, adrenaline and dopamine. Noradrenaline is the neurotransmitter in sympathetic nerve endings, while the adrenal medulla secretes mainly adrenaline. The reason for this difference is that adrenaline synthesis from noradrenaline is catalyzed by an enzyme, phenylethanolamine-N-methyltransferase (PNMT), which is absolutely dependent on induction by glucocorticoids (Wurtman and Axelrod, 1966); only in the normal adrenal medulla is there a high local concentration of Cortisol due to the portocapillary circulation from cortex to medulla. There is little circulating dopamine, whereas in urine, dopamine is the predominant catecholamine. It is formed within the kidney from circulating DOPA (Brown and Dollery, 1981), but earlier reports that it may have a natriuretic action have not been confirmed (Alexander et al., 1974; Oates et al., 1979).