Diamine Oxidase in Blood Plasma in Some Vertebrates and Anodonta cygnea before and after Injection of Heparin

Abstract

Abstract After intravenous injection of heparin (in aniounts related to the body‐weight) thc blood plasma diamine oxidase(DAO‐) activity increased transiently in all vertebrates studied (cod, frog, fowl, mouse, white rat, golden hamster, guinea‐pig, rabbit, cat, dog, goat, sheep and cow). The DAO‐response to heparin varied strongly between the species. Often with a bi‐phasic ascent, it showed a maximum (within a few minutes to about one hour) and then decreased, often in a “monoexponential” fashion, in the course of the next few hours. In anodons no significant DAO‐activity was found.—The biological significance of the heparin effect upon DAO is discussed with special reference to the coexistence of heparin and histamine in the mast cells.