Urinary Excretion of the Serotonin Metabolite, 5-Hydroxyindoleacetic Acid, in Various Clinical Conditions

Abstract

CONSIDERABLE interest is being given to the possible role of serotonin (5-hydroxytryptamine) in various physiologic and pathologic processes. This amine is found primarily in the gastrointestinal tract, blood platelets and brain of mammalian species.^{1 2 3 4} Although the physiologic role of serotonin is unknown, it is a potent stimulant of smooth muscle in the gastrointestinal tract, bronchi and blood vessels.^{5 , 6} The point has been raised that it may be involved in the maintenance of normal intestinal motility⁷ and in hemostasis.^{8 9 10} The amine has also been considered a hormone regulating the circulation and function of the kidney.⁵ On the basis of the observation . . .