Measurement and characterization of histamine and methylhistamine in human urine under histamine-rich and histamine-poor diets.
A radioimmunoassay for histamine was used to measure histamine and 1-methylhistamine (MH) in human urine samples. The detection limit of this assay was 2 ng/ml for histamine and 0.5 ng/ml for MH. Cation exchange high performance liquid chromatography (HPLC) on a Bio-Gel TSK SP-5 PW column with gradient elution was capable of separating histamine from its precursor L-histidine and its metabolites MH and 1-methylimidazole acetic acid (MIAA). The concentration of MH-immunoreactive materials in healthy volunteers with no dietary restrictions was 202 +/- 92 micrograms/24 h (mean +/- SD; n = 14). The excretion of MH-like material, expressed as micrograms of MH per 24 h, was not significantly different before or after the intake of histamine-rich food: 217 +/- 88 vs. 276 +/- 135 micrograms/24 h (n = 10). However, in urine samples collected in individual fractions, the levels of MH immunoreactivity were significantly increased after a histamine-rich meal in comparison to the corresponding fractions which were taken a day earlier at the same time intervals after a histamine-low diet (p < 0.03). HPLC characterization of MH immunoreactivity revealed the presence of histamine, MH and a compound with the same retention time as MIAA. The ratio of histamine, MH and MIAA in controls without dietary restrictions, as determined by HPLC analysis, was 50 +/- 6, 47 +/- 5 and 3 +/- 1%, respectively. After a histamine-rich meal the ratio was 97 +/- 2% for histamine, 1% for MH and 2 +/- 1% for MIAA.
Department of Dermatology, University Hospital Eppendorf, University of Hamburg, FRG.
K
K
Hermann
B
B
Hertenberger
J
J
Ring
D000328:Adult; D002851:Chromatography, High Pressure Liquid; D004032:Diet; D005260:Female; D006632:Histamine / Q000008:administration & dosage / Q000276:immunology / Q000652:urine*; D006801:Humans; D008297:Male; D008761:Methylhistamines / Q000276:immunology / Q000652:urine*; D011863:Radioimmunoassay
D008761:Methylhistamines; D006632:Histamine