Fully automated high-performance liquid chromatographic assay for the analysis of free catecholamines in urine

Said, Rana; Robinet, D.; Barbier, Charlotte; Sartre, Jean‐Paul; Huguet, Carme

doi:10.1016/s0378-4347(00)82297-5

Cited by 16 publications

(4 citation statements)

References 20 publications

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“…Several previous works included automated concentration step of CAs prior to HPLC, in which materials were used such as activated alumina (AL) cartridges (Said et al, 1990) or columns (De Jong et al, 1987), dihydroxyborylsilica (DHBS) columns (De Jong et al, 1987) and an ionexchange precolumn (Kitahashi et al, 1991). The latter has been used for the automated CA analyser with electrochemical detection.…”

Section: Resultsmentioning

confidence: 99%

A fully automated HPLC method for the determination of catecholamines in biological samples utilizing ethylenediamine condensation and peroxyoxalate chemiluminescence detection

Prados¹,

Higashidate²,

Imai³

1994

Biomedical Chromatography

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A fully automated in-line extraction reversed-phase high-performance liquid chromatography (HPLC) method with chemiluminescence detection was developed for the analysis of human and rat plasma catecholamines (CAs), norepinephrine (NE), epinephrine (E) and dopamine (DA). N-Methyldopamine (N-MeDA) was used as an internal standard. The method involves collection of plasma samples, which are first diluted with a sample dilution buffer containing N-MeDA, and in-line extraction of CAs using a carboxylic acid small resin precolumn (SERUMOUT-CEX). This pre-extraction process was coupled with an HPLC system including reversed-phase mode separation on an analytical column (TSK gel ODS-80Ts), fluorogenic derivatization with ethylenediamine (ED) and finally postcolumn peroxyoxalate chemiluminescence reaction detection using bis [4-nitro-2-(3,6,9-trioxadecyloxycarbonyl)phenyl]oxalate (TDPO) and hydrogen peroxide. The optimized mobile phase compositions, flow rates, operation timing for the adsorption and desorption of CAs in the precolumn, the separation in the analytical column and the optimum fluorogenic and chemiluminogenic reaction conditions were investigated. The detection limit for all the CAs was about 1 fmol (signal-to-noise ratio is 2). Excellent linearity of the calibration curves for CAs was observed in the range from 5 to 500 fmol for each CA using the internal standard. The relative standard deviations of the method for determining NE (183 fmol), E (23.6 fmol) and DA (6.1 fmol) in 50 microL of human plasma (n = 3) were 2.8, 2.7 and 3.1%, respectively, for the within-day assay and 5.0, 3.8 and 4.0%, respectively, for the between-day assay. The method was applicable to the determination of CAs in 25-50 microL of human or rat plasma.

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Section: Resultsmentioning

confidence: 99%

A fully automated HPLC method for the determination of catecholamines in biological samples utilizing ethylenediamine condensation and peroxyoxalate chemiluminescence detection

Prados¹,

Higashidate²,

Imai³

1994

Biomedical Chromatography

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“…Purified melanosomes were immediately resuspended in 100 µl heptanesulphonic acid buffer pH 4·0 (6 10 3 M sodium heptanesulphonate (Fluka Chemicals, Gillingham, Kent, UK) and 7·5 10 2 M sodium dihydrogen orthophosphate dihydrate (Fisher Chemicals)) and snap frozen in liquid nitrogen according to the method of Said et al (1990). Extracts were prepared in a micro-pestle and mortar as previously described and the supernatant de-proteinised by the addition of 5% (v/v) 2 N perchloric acid.…”

Section: Detection Of L-dopa In Melanosomes By Hplcmentioning

confidence: 99%

A novel mechanism in control of human pigmentation by β-melanocyte-stimulating hormone and 7-tetrahydrobiopterin

Spencer¹,

Chavan²,

Marles³

et al. 2005

Journal of Endocrinology

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The human skin holds the full machinery for proopiomelanocortin processing. The -melanocytestimulating hormone ( -MSH)/melanocortin-1-receptor cascade has been implicated as a major player via the cAMP signal in the control of melanogenesis. Only very recently the -endorphin/µ-opiate receptor signal has been added to the list of regulators of melanocyte dendricity and melanin formation. In this context it was reported that (6R)--erythro-5,6,7,8-tetrahydrobiopterin (6BH 4 ) can act as an allosteric inhibitor of tyrosinase, the key enzyme in melanogenesis, and this inhibition is reversible by both -and -MSH. It was also shown earlier that 7BH 4 , the isomer of 6BH 4 , is twice as active in this inhibition reaction. However, as yet it is not known whether 7BH 4 is indeed present in loco in the melanosome. We here provide evidence that this isomer is present in this organelle in a concentration range up to 50 10 6 M. Determination of -MSH in melanosomal extracts yielded 10 pg/mg protein. Moreover, we demonstrate reactivation of the 7BH 4 /tyrosinase inhibitor complex by -MSH, whereas -MSH failed to do so. Furthermore, we show intra-melanosomal -dopa formation from dopachrome by 7BH 4 in a concentration range up to 134 10 6 M. Based on these results, we propose a new receptorindependent mechanism in the control of tyrosinase/ melanogenesis by -MSH and the pterin 7BH 4 .

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“…A number of diseases are related to catecholamines dysfunction such as Parkinson's disease, hypertension, and certain neural tumours such as pheochromocytoma and neuroblastoma. These diseases may be characterized by the release of abnormally high quantities of amines and their metabolites, such as VMA (vanillylmandelic acid) and HVA (homovanillic acid) in the urine [33,34]. Therefore, the determination of various catecholamines and their metabolites is very useful in etiological investigations, diagnosis, and the follow-up of catecholamine-related diseases.…”

Section: Discussionmentioning

confidence: 99%

Metabolism of Homovanillamine to Homovanillic Acid in Guinea Pig Liver Slices

Panoutsopoulos

2005

Cell Physiol Biochem

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Background/Aims: Homovanillamine is a biogenic amine that it is catalyzed to homovanillyl aldehyde by monoamine oxidase A and B, but the oxidation of its aldehyde to the acid derivative is usually ascribed to aldehyde dehydrogenase and a potential contribution of aldehyde oxidase and xanthine oxidase is usually ignored. Methods: The present investigation examines the metabolism of homovanillamine to its acid derivative by concurrent incubation with monoamine oxidase and aldehyde oxidase. In addition, the metabolism of homovanillamine in freshly prepared and cryopreserved liver slices is examined and the relative contribution of aldehyde oxidase, xanthine oxidase and aldehyde dehydrogenase activity by using specific inhibitors of each oxidizing enzyme is compared. Results: Homovanillamine was rapidly converted mainly to homovanillic acid when incubated with both momoamine oxidase and aldehyde oxidase. Homovanillic acid was also the main metabolite in the incubations of homovanillamine with freshly prepared or cryopreserved liver slices, via the intermediate homovanillyl aldehyde. The acid formation was 70-75 % inhibited by disulfiram (specific inhibitor of aldehyde dehydrogenase), whereas isovanillin (specific inhibitor of aldehyde oxidase) inhibited acid formation to a lesser extent (50-55 %) and allopurinol (specific inhibitor of xanthine oxidase) had almost no effect. Conclusions: Homovanillamine is rapidly oxidized to its acid, via homovanillyl aldehyde, by aldehyde dehydrogenase and aldehyde oxidase with little or no contribution from xanthine oxidase.

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Fully automated high-performance liquid chromatographic assay for the analysis of free catecholamines in urine

Cited by 16 publications

References 20 publications

A fully automated HPLC method for the determination of catecholamines in biological samples utilizing ethylenediamine condensation and peroxyoxalate chemiluminescence detection

A fully automated HPLC method for the determination of catecholamines in biological samples utilizing ethylenediamine condensation and peroxyoxalate chemiluminescence detection

A novel mechanism in control of human pigmentation by β-melanocyte-stimulating hormone and 7-tetrahydrobiopterin

Metabolism of Homovanillamine to Homovanillic Acid in Guinea Pig Liver Slices

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