Studies on ali-esterases and other lipid-hydrolysing enzymes. 2. The effect of heparin injection on alimentary lipaemia and on the plasma esterases

Abstract

The effect was investigated in 6 species of animals. In all cases the post-heparin plasma contained a factor capable of clearing lipemic plasma. The injection of heparin in man, dog and rat liberates a tributyrinase into the plasma which is not inhibited in vitro by low concentrations of eserine or diisopropyl p-nitro-phenyl phosphate (DINP). The DINP-resistant tributyrinase activity of rabbit, mouse and guinea pig plasma does not increase markedly after the injection of heparin. Both the clearing factor and the DINP- resistant tributyrinase in post-heparin plasma are inactivated by heating at 48-50[degree] or by incubation with diethyl p-nitrophenyl phosphate (E600). However, the tributyrinase is less sensitive than the clearing factor to destruction by heating and more sensitive to inhibition by E600. The clearing factor and the DINP-resistant tributyrinase are different enzymes, both of which may be liberated from the tissues into the blood stream by the injection of heparin.