Gas chromatographic-mass spectrometric assay to measure urinary N tau-methylhistamine excretion in man.
An assay has been developed for N tau-methylhistamine, a major metabolite of the autocoid histamine, based on gas chromatography-electron-capture negative-ion chemical ionisation mass spectrometry. N tau-Methylhistamine was extracted from urine by cation-exchange chromatography and converted to its di-(3,5-bistrifluoromethylbenzoyl) derivative. The latter has good chromatographic properties and gives a negative-ion mass spectrum with the molecular ion (M., m/z 605) as base peak. A commercially available trideuterated analogue of N tau-methylhistamine was used as internal standard. Basal urinary excretion of N tau-methylhistamine in five normal subjects was found to be 0.21 +/- 0.05 mumol/h (289 +/- 74 mumol/mol of creatinine). This value was not significantly altered in these subjects following the infusion of a subpharmacological dose of histamine. In eight atopic volunteers, basal urinary excretion of N tau-methylhistamine was also not significantly changed following challenge with inhaled allergen.
Department of Clinical Pharmacology, Royal Postgraduate Medical School, London, U.K.
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S
Murray
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Wellings
I K
IK
Taylor
R W
RW
Fuller
G W
GW
Taylor
D000328:Adult; D000485:Allergens / Q000009:adverse effects; D002852:Chromatography, Ion Exchange; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006632:Histamine / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D007202:Indicators and Reagents; D008297:Male; D008761:Methylhistamines / Q000737:chemistry / Q000652:urine*; D012015:Reference Standards
D000485:Allergens; D007202:Indicators and Reagents; D008761:Methylhistamines; C031205:3-methylhistamine; D006632:Histamine