The effect of heparin on diamine oxidase and lipoprotein lipase in human lymph and blood plasma.

Abstract

In two men and one woman the diamine oxidase (DAO) and lipoprotein lipase (LL) activities were determined by micromethods in lymph and blood plasma before injection of heparin intravenously and thereafter followed during the next two hours.The DAO activity in thoracic duct lymph was much higher than in blood plasma. The injection of heparin was followed by a prompt rise in blood plasma of DAO (about 20-fold) and, with some delay, in the central lymph (about 200-fold). The maximal DAO activity in thoracic duct lymph was about 250 times higher than in blood plasma.The heparin-induced increase of the plasma-DAO seems, in contrast to the plasma-LL, to be partially mediated by the lymph.The significance of these findings in the investigation of the rate of elimination of plasma-DAO, as well as the role played by the lymph vessels in organ preparations for study of the enzyme liberation after endogenous heparin in anaphylactic shock are briefly discussed.