'"Hepatic" and "Extrahepatic" Triglyceride Lipase Activity in Post-Heparin Plasma of Normals and Patients with Cirrhosis of the Liver

Abstract

In normals and in patients with cirrhosis of the liver triglyceride lipase (TGL) activity of post-heparin plasma was measured both with and without preincubation of the enzyme with protamine sulfate. In the patients with cirrhosis of the liver the protamine-resistant TGL activity was greatly reduced while the protamine-inactivated TGL activity was normal when compared with the control group. No inhibitor of the post-heparin TGL could be detected in the serum of the cirrhotics. In some patients with markedly impaired liver function the activity of the protamine-resistant TGL of post-heparin plasma was reduced to nearly zero. In agreement with the results obtained by others from animal experiments, this finding indicates that the protamine-resistant TGL of post-heparin plasma is of hepatic origin, while the protamine-inactivated TGL is released from extrahepatic tissues. In the post-heparin plasma of normal individuals, "hepatic" TGL activity was about twice as high as the "extrahepatic" TGL activity when measured with an artificial substrate.

Key words

Triglyceride Lipase - Post-Heparin Plasma - Liver Disease