Journal of Lipid Research, Vol 17, 498-505, Copyright © 1976 by Lipid Research, Inc.
Effect of an anti-lipoprotein lipase serum on plasma triglyceride removal
IP Kompiang, A Bensadoun and MW Yang
Anti-lipoprotein lipase sera injected intravenously in roosters blocked
quantitatively the catabolism of very low density lipoprotein (VLDL)
triglyceride. Antibodies were produced in rabbits immunized with highly
purified lipoprotein lipase (LPL, glycerol ester hydrolase, E C 3.1.1.3)
prepared from chicken adipose tissue. Following anti-LPL serum injection
there was a linear increase in plasma triglyceride concentration. The rate
of entry of triglyceride in plasma was estimated from the rate of
triglyceride accumulation in the plasma of animals injected with anti-LPL
serum, or from the disappearance curve of biologically labelled VLDL. In
instances where both measurements were conducted in the same animals there
was very close agreement between the two procedures. Inhibition of VLDL
triglyceride catabolism of anti-LPL serum provided a way to characterize
newly secreted VLDL that exhibited a broad spectrum of particle sizes with
a median of 625 A degrees. They contained 76.2 +/- 1.2% triglyceride and
had a high ratio of free to ester cholesterol (2.46 +/- 0.45). In control
VLDL samples there was 46.1% triglyceride, and the ratio of free to ester
cholesterol was 1.19. The complete inhibition of triglyceride removal by an
antiserum prepared against adipose tissue LPL demonstrates that the
NaCl-inhibited, serum-activated lipase prepared by affinity chromatography
on heparin-Sepharose and concanavalin A-Sepharose columns is the enzyme
responsible in vivo for the catabolism of VLDL triglyceride. Further, the
kinetics of triglyceride accumulation in the plasma provide evidence that
the site of degradation of VLDL triglyceride is within the plasma
compartment.