SIMULTANEOUS DETERMINATIONS OF HISTAMINE AND N-TAU-METHYLHISTAMINE BYHIGH-PERFORMANCE LIQUID CHROMATOGRAPHY-CHEMILUMINESCENCE COUPLED WITHIMMOBILIZED DIAMINE OXIDASE

A method for the simultaneous determinations of histamine and its meta bolite N-tau-methylhistamine by HPLC-chemiluminescence coupled with im mobilized diamine oxidase was developed. The method was based on the d etermination of chemiluminescence formed by the reaction of a luminol- ferricyanide mixture in alkaline medium with hydrogen peroxide which i s one of the metabolic products of histamine and N-tau-methylhistamine formed by diamine oxidase. HPLC with postcolumn derivatization result ed in good separation of the two amines and gave linear relationships between the concentrations of both and their chemiluminescence intensi ties. The lower limits of chemiluminescent detection of histamine and N-tau-methylhistamine were 5 and 10 pmol, respectively. The immobilize d column showed good operational stability for more than 1 month, duri ng which period 200 samples were analyzed. With this system, the hista mine contents of the cerebral cortex, forestomach, glandular stomach, and kidney of Wistar rats were found to be 0.30, 58, 396, and 2.4 nmol /g wet wt, respectively. These values are very similar to those determ ined by HPLC-fluorometry. The N-tau-methylhistamine contents of these tissues were 0.36, 0.40, 0.72, and 3.8 nmol/g wet wt, respectively. Th is method will be useful for studying the roles of histamine in both b rain and peripheral tissues. (C) 1995 Academic Press, Inc.