Combined decrease of postheparin-diamine oxidase (histaminase) and postheparin-lipoproteinlipase in inflammatory diseases.

Diamine oxidase (DAO, histaminase), according to Schayer, is an essential enzyme in histamine metabolism. It metabolises also a variety of diamines such as putrescine and cadaverine and is generally accepted to be identical with histaminase. Lipoproteinlipase (LL) is assumed to play an essential role in lipid metabolism. In vertebrates, parenterally applied heparin causes a marked dose-dependent rise of the plasma level of both enzymes mainly due to the release from the enzyme containing organs. The plasmatic level changes of DAO and LL after heparin application (200 U/kg b.wt., i.v.) have been studied in 30 patients suffering from 20 different, predominantly inflammatory diseases. In all cases the release of postheparin diamine oxidase (PHD) and of post-heparin lipoproteinlipase (PHLA) was found to be markedly decreased. There existed a highly significant correlation between the degree of the release of both enzymes (r=0.843, p less than 0.0005). In all patients normal levels of plasma insulin were detected. No correlation was found between PHLA and plasma triglycerides levels. Decrease of PHD respectively PHLA was a more sensitive biochemical parameter than were changes of serum glutamic pyruvic transaminase in acute hepatitis and of C reactive protein (CRP) in chronic inflammatory kidney diseases. This finding is most likely a general phenomenon in inflammatory diseases. Besides hormonal regulation inflammation-dependent effects on PHLA have to be discussed.