Abstract

A sensitive, specific and relatively simple and rapid enzymatic-isotopic method for the estimation of histamine in biologic materials is described. Tissues are incubated with tracer amounts of H³-histamine and C¹⁴-S-adenosylmethionine in the presence of the enzyme, histamine methyl transferase, which specifically methylates histamine. H³-C¹⁴-methylhistamine istamine is the only radioactive product extracted. The ratio of C¹⁴/H³ is directly proportional to the amount of unlabeled tissue histamine present in the incubation mixture. This assay can be utilized to detect as little as 2 ng of tissue histamine.