Systematic analysis of histamine and N-methylhistamine concentrations in organs from two common laboratory mouse strains: C57Bl/6 and Balb/c

Objective Histamine plays a role in several (patho) physiological processes that are commonly studied in mouse models. However, a systematic quantification of histamine and its metabolite N-methylhistamine in mouse organs has not been reported so far. Methods Balb/c and C57Bl/6 mice were grouped according to their sex and age. Brains, hearts, lungs, livers, kidneys, stomachs, intestines, thymi, spleens, and lymph nodes were excised, weighed, and homogenized. Histamine and N-methylhistamine were quantified simultaneously by a HPLC-mass spectrometry method. Results In all organs analyzed, histamine and N-methylhistamine were detected; however, with quantitative differences. Histamine was present most abundantly in the stomach, lymph nodes, and thymus. The lowest histamine concentrations were detected in brain, liver, lung, and intestine. In most organs, the histamine concentrations increased age-dependently. Substantial concentrations of N-methylhistamine were detected only in lung, intestine and kidney, while in all other organs it was present only in minor quantities. Conclusion HPLC-mass spectrometry is a useful method for the highly sensitive and simultaneous detection of histamine and N-methylhistamine. Histamine is present in virtually all organs, not only in those traditionally associated with histamine-mediated disease. Highest concentrations are found in stomach, lymph node, and thymus; medium concentrations in heart, spleen, and kidney; and lowest concentrations detected in intestine, brain, liver, and lung.