| catecholamine | <biochemistry, investigation, physiology> A type of biogenic amine derived from tyramine, characterised as alkylamino derivatives of ortho-dihydroxyphenylalkylamines in turn derived from tyrosine. Catecholamines include adrenaline, noradrenaline and dopamine, with roles as hormones and neurotransmitters. Measurement of noradrenaline and adrenaline can be made in blood and urine. Elevations may be seen in pheochromocytoma or neuroblastoma. Normal blood levels of adrenaline should be: 20 ng/ml and normal blood levels of noradrenaline should be 60 ng/ml. (16 Mar 1998) |
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| blood catecholamine | <investigation> The measurement of noradrenaline and adrenaline in the blood. Often these same catecholamines can be measured in the urine. Elevations may be seen in pheochromocytoma or neuroblastoma. Normal blood levels of adrenaline should be: 20 ng/ml and normal blood levels of noradrenaline should be 60 ng/ml. (05 Jan 1998) |
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| receptors, catecholamine | Cell surface proteins that bind catecholamines with high affinity and trigger intracellular changes which influence the behaviour of cells. The catecholamine messengers epinephrine, norepinephrine, and dopamine are synthesised from tyrosine by a common biosynthetic pathway. (12 Dec 1998) |
| total catecholamine test | A fluorometric determination of catecholamines in 24-hr urine specimens; elevated values are seen in patients with pheochromocytoma and neuroblastoma; spurious elevations may be seen due to excretion products of medication containing adrenaline, tetracyclines, quinidine, and some antihypertensive agents; false-positive elevations may be seen in persons with extensive burns, in vigorous exercise, or in progressive muscular dystrophy. (05 Mar 2000) |
| urine catecholamine | A test that measures the level of catecholamines or their metabolites in the urine. A 24 hour urine sample is necessary for this assay. Elevations may be seen in pheochromocytoma or neuroblastoma. Normal urine levels of adrenaline should be: 0.5 to 20 mcg/ml and normal urine levels of noradrenaline should be 15 to 80 mcg/ml. (27 Sep 1997) |