Urine catecholamines in pheochromocytoma by rat blood pressure bioassay
Sivam, S.P.; Bharadwaj, S.L.; Singh, D.; Rawat, S.S.; Grover, J.K.
Indian Journal of Medical Research 77: 879-885
1983
ISSN/ISBN: 0019-5340 PMID: 6642586 Document Number: 215341
Free catecholamines (adrenaline urine were bioassayed using blood pressure of the anaesthetized rat. The mean 24 h urine catecholamine level in 40 normal adult volunteers was 32.2 .mu.g .+-. 4.9 (SE; range 8-95 .mu.g). In 775 hypertensive patients not suspected of pheochromocytoma, the mean daily catecholamine level was 25.6 .+-. 0.68 (SE; range 3-95), indicating a normal turnover. In 20 cases of proved pheochromocytoma, the mean daily catecholamine levels before and after surgical removal were 1040.4 .mu.g (range 61-7500 .mu.g) and 44.67 .+-. 6.17 (SE; range 10-95 .mu.g), respectively. HCl alone is a good preservative of urine catecholamines; ascorbic acid fed or added to urine offers no convincing advantage over HCl; HCl added urine preserves well at 8.degree. C for at least 7 days; urine acid hydrolysis to release inactive conjugate is not necessary; 1-6 h urine sample serves the purpose if 24 h collection is not possible and normal urinary catecholamine values do not necessarily exclude pheochromocytoma. One of 20 cases in the series showed normal values over a 2 mo. period. This reliable, inexpensive bioassay method for a diagnosis of pheochromocytoma is recommended particularly when facilities for carrying out the more expensive chemical assay are not available.