Some examples of the clinical importance of the basic and heparin-induced phospholipase A in human plasma

Phospholipase A activity was determined in human plasma with biological ³²P-labelled phosphatidylethanolamine from rat liver following cardiac operations with the aid of the heart-lung-machine. The basic activity before heparin and the initiation of bypass was 72 nmol β ml^?1 β h^?1 plasma; thereby large differences in the basic activity were detected between cyanotic and acyanotic heart diseases. A sharp increase of phospholipase activity was observed after heparin (a smaller one in intensive care patients with low-dose heparin), and a further increase up to the end of perfusion. Normal values are reached after giving protamine at the end of the operation. An important role for plasma phospholipase in the regulation of physiological and pathophysiological processes may be supposed from these results.