5-Hydroxyindoleacetic acid assay

Serotonergic function has been investigated by using multiple methods. Assaying the major metabolite of serotonin, 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF) has been widely used (Ch. 13). This method assumes that CSF 5-HIAA is related to brain serotonin activity. This premise is supported by the rostral-caudal concentration gradient of CSF 5-HIAA and the observation in postmortem studies that CSF 5-HIAA correlates with levels of 5-HIAA in prefrontal cortex [16], both of which suggest that CSF 5-HIAA is a reasonable index of prefrontal serotonin turnover. ... 

Colorimetric assays used in endocrinological procedures are also often subject to drug interference. We have observed an interesting interference in a patient with carcinoid. The patient excreted 400 mg of 5-hydroxyindoleacetic acid (5-HIAA) and when a vanillylmandclic acid (VMA) determination was performed by a nonspecific diazo method, the value was reported to be 375 mg. The catecholamines were just above normal. There was an immediate suggestion that the patient also had a pheochromocytoma. However, when a specific chromatographic VMA method was used, the value was found to be within normal limits. Subse-... 

Indolealkylamines. GC-MS methods applied in studies of the biochemical pharmacology of indoleamines parallel work on the catecholamines. SIM assays for serotonin (5-hydroxytryptamine), 5-methoxytryptamine, JV-acetylserotonin and melatonin (5-methoxy-N-acetyltryptamine) in rat pineal and brain tissue have been described [453,469]. Pentafluoro-propionyl derivatives and structural homologue standardisation were employed with detection limits in the subpicomole range. Estimation of central indoleamine turnover in man currently depends upon metabolite determination in CSF. Ion monitoring determination of indole-3-acetic acid [454] a metabolite of tryptamine, and isotope dilution assays for 5-hydroxyindoleacetic acid (5-HIAA) [455,458] have been reported. Serotonin is converted by central monoamine oxidase to 5-HIAA and the measurement of this metabolite, formerly by fluorimetry, is of interest in patients with CNS disorders [470]. GC-MS has also contributed to the identification of N,N-dimethyltryptamine in vitro [471] and isotope dilution technique has been applied to the measurement of this metabolite in control subjects and in psychiatric patients [472]. 

Yeung PK, Buckley SJ, Pedder SC, Dingemanse J. Determination of 3,4-dihydroxyphenylacetic acid and 5-hydroxyindoleacetic acid in human plasma by a simple and rapid high-performance liquid chromatography assay. J Pharm Sci 1996 85 451-3. 

The determination of catecholamines requires a highly sensitive and selective assay procedure capable of measuring very low levels of catecholamines that may be present. In past years, a number of methods have been reported for measurement of catecholamines in both plasma and body tissues. A few of these papers have reported simultaneous measurement of more than two catecholamine analytes. One of them utilized lised UV for end-point detection and the samples were chromatographed on a RP phenyl analytical column. The procedure was slow and cumbersome because ofdue to the use of a complicated liquid-hquid extraction and each chromatographic run lasted more than 25 min with a detection Emit of 5-10 ng on-column. Other sensitive HPLC methods reported in the hterature use electrochemical detection with detection limits 12, 6, 12, 18, and 12 pg for noradrenaline, dopamine, serotonin, 5-hydroxyindoleacetic acid, and homovanillic acid, respectively. The method used very a comphcated mobile phase in terms of its composition whilewhilst the low pH of 3.1 used might jeopardize the chemical stabihty of the column. Analysis time was approximately 30 min. Recently reported HPLC methods utilize amperometric end-point detection. " ... 

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