Function of hepatic triglyceride lipase in lipoprotein metabolism.
Rat hepatic triglyceride lipase (H-TGL) was purified from liver tissue extracts by affinity chromatography on Sepharose 4B with covalently linked heparin. The purified rat H-TGL exhibited the properties previously described for this enzyme. Enzyme protein was injected into rabbits for anti-H-TGL antibody production. Antirat-H-TGL did not react against rat lipoprotein lipase (LPL) but inhibited H-TGL-activity both in vitro and in vivo greater than 90%. These antibodies were injected into rats and lipoprotein analyses were performed over a 36-hr period. It could be shown that inactivation of H-TGL by anti-H-TGL gamma-globulins in vivo led to an increase in total triglyceride concentration from 70 mg/dl to 230 mg/dl due to an increase in very low density lipoprotein (VLDL) and low density lipoprotein (LDL) triglycerides 4 hr after antibody injection; a marked increase in high density lipoprotein (HDL) phospholipid concentration was observed with almost no change in HDL-cholesterol and HDL-triglycerides. This study documents the ability of antirat-H-TGL-gamma-globulins to inhibit H-TGL in vitro and in vivo. Furthermore, the inhibition of triglyceride removal in vivo demonstrated that this enzyme together with LPL is responsible for the catabolism of VLDL-triglyceride.
D000273:Adipose Tissue / Q000201:enzymology; D000818:Animals; D007118:Immunoassay; D007700:Kinetics; D008049:Lipase / Q000302:isolation & purification / Q000378:metabolism*; D008074:Lipoproteins / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D008297:Male; D051381:Rats; D005719:gamma-Globulins
D008074:Lipoproteins; D005719:gamma-Globulins; D008049:Lipase