Intestine 5-hydroxyindoles

Ml) Carcinoid tumor. Elevated 5-hydroxyindole acetate (5-HIAA) occurs in carcinoid tumors of the intestine, where argentaffin cells secrete excess 5-hydroxytryptamine (serotonin). The patient experiences flushing, diarrhea, hypotension, and bronchoconstriction. (It is possible that these symptoms may relate to other chemidals also produced by argentaffin cells). 

Taking a concentration of 5-hydroxytryptamine of 0-05 jug/ml in the blood and an excretion of 3-6 mg per day of 5-hydroxyindole acetic acid as a basis, Erspamer estimated that the amount of 5-hydroxytryptamine contained in the total blood volume is metabolized every 2-3 hr. Heissel " found that C-marked serotonin in the thrombocytes of eleven healthy subjects had a half-life of 5-6 days. Sjoerdsma et found a pool of 2800 mg 5-hydroxytryptamine with a half-life of 5 days in a patient with a metastasized carcinoid of the small intestine after intravenous injections of C-marked hydroxytryptophane. Zucker et found a half-life of 1-7-2-8... 

Rosenberg, J. C., Davis, R., Moran, W. H. and Zimmermann, B., Serum serotonin concentration and urinary 5-hydroxyindole acetic acid excretion following intestinal obstruction and resection. Fed. Proc. 18, 503 (1959). 

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