Plasma 5-hydroxyindoleacetic acid

Degg TJ, Allen KR, Barth JH. Measurement of plasma 5-hydroxyindoleacetic acid in carcinoid disease an alternative to 24-h urine collections Ann Clin Biochem 2000 37 (Pt 5) 724-6. 

B.-M. Eriksson and B.-A. Persson, Determination of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid in plasma by direct injection in coupled-column liquid clrromatography with electrochemical detection , 7. Chromatogr. 459 351-360 (1988). 

In contrast, much is known about the catabolism of catecholamines. Adrenaline (epinephrine) released into the plasma to act as a classical hormone and noradrenaline (norepinephrine) from the parasympathetic nerves are substrates for two important enzymes monoamine oxidase (MAO) found in the mitochondria of sympathetic neurones and the more widely distributed catechol-O-methyl transferase (COMT). Noradrenaline (norepinephrine) undergoes re-uptake from the synaptic cleft by high-affrnity transporters and once within the neurone may be stored within vesicles for reuse or subjected to oxidative decarboxylation by MAO. Dopamine and serotonin are also substrates for MAO and are therefore catabolized in a similar fashion to adrenaline (epinephrine) and noradrenaline (norepinephrine), the final products being homo-vanillic acid (HVA) and 5-hydroxyindoleacetic acid (5HIAA) respectively. 

Celada P, Perez J, Alvarez E, Artigas F. Monoamine oxidase inhibitors phenelzine and brofaromine increase plasma serotonin and decrease 5-hydroxyindoleacetic acid in patients with major depression relationship to clinical improvement. J Clin Psychopharmacol 1992 12 309-315. 

Celada P, Sarrias MJ, Artigas F. Serotonin and 5-hydroxyindoleacetic acid in plasma. Potential use as peripheral measures of MAO-A activity. J Neural Transm 1990 32(Suppl 1) 149-154. 

A boy (3.4 kg) was bom by cesarean section, because of fetal distress, to a mother who had taken paroxetine (40 mg/day) and olanzapine (10 mg/day) until 48 hours before delivery (84). After delivery, the baby had increased tone and was hypoglycemic. The next day he was increasingly jittery, with profuse salivation. At 44 hours there was no detectable paroxetine or olanzapine in the neonatal plasma and CSF concentrations of the 5HT metabolite, 5-hydroxyindoleacetic acid (5HIAA) were normal. The baby s condition improved... 

Preliminary evidence suggests that dietary essential fatty acids, including DHA, may change neurotransmitter concentrations. Plasma DHA concentrations were shown to be negatively correlated with cerebrospinal fluid 5-hydroxyindoleacetic acid in violent subjects (Hibbeln et al., 1998). 

Serotonin. Many fruits and vegetables that contain 5-hydroxytryptamine (serotonin), such as bananas, cause an increased excretion of 5-hydroxyindoleacetic acid. Avocados impair glucose tolerance by affectmg insulin secretion. Onions reduce both the plasma glucose and insulin response to glucose. 

Caffeine, Caffeine is contained in many beverages, including coffee, tea, and colas and has considerable effect on the concentration of blood constituents. Caffeine stimulates the adrenal medulla, causing an increased excretion of the catecholamines and their metabolites and a slight increase in the plasma glucose concentration with impairment of glucose tolerance. The adrenal cortex is also affected plasma cortisol is increased, accompanied by increased excretion of free cortisol, 11-hydroxycorticoids, and 5-hydroxyindoleacetic acid. The effect of caffeine may be so great that the normal diurnal variation of plasma cortisol may be suppressed. 

Smoking affects both the adrenal cortex and the medulla plasma 11-hydroxycorticosteroids may be increased by 75% with heavy smoking. In addition, the plasma cortisol concentration may increase by as much as 40% within 5 minutes of the start of smoking, although the normal diurnal rhyth-micity of cortisol is unaffected. Smokers excrete more 5-hydroxyindoleacetic acid than do nonsmokers. 

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. " ... 

Fig. 2.3. Diagnostic flow-chart in the differentiation of defects of biogenic amine neurotransmitter metabolism. The correct differential diagnosis depends on the pattern of amines and their metabolites in either urine, CSF or plasma. represents increased values, [ represents lowered values. 5HIAA 5-hydroxyindoleacetic acid HVA homovanillic acid 5HT serotonin 30MD 3-0-methyldopa DOPAC dihydroxyphenylacetic acid 3MT 3-methoxytyramine NMN norme-tanephrine VMA vanillylmandelic acid DOPS dihydroxyphenylserine MHPG 3-methoxy-4-hydroxyphenylglycol Y yes N no. Plasma and CSF levels have not been analysed but they probably reflect those seen in urine. For interpretation of quantitative results see pathological values.

Sagara, Y. Okatani, Y. Yamanaka, S. Kiriyama, T. Determination of plasma 5-hydroxytryptophan, 5-hydroxytryptamine, 5-hydroxyindoleacetic acid, tryptophan and melatonin by high-performance liquid chromatography with electrochemical detection, J.Chromatogr., 1988, 431, 170-176. 

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