AJP - Gastrointestinal and Liver Physiology, Vol 247, Issue 3 305-G310, Copyright © 1984 by American Physiological Society
Apoprotein C effect on triglyceride transport in tandem-perfused rat hind end and liver
W. J. Kortz, J. R. Nashold, M. R. Greenfield, H. Hilderman and S. H. Quarfordt
The metabolism of double-labeled triglyceride in a synthetic emulsion was
defined in an in vitro perfusion system of rat hind end and liver described
previously [Am. J. Physiol. 245 (Gastrointest. Liver Physiol. 8):
G106-G112, 1983]. The metabolism of [3H]glycerol-[14C]triolein was defined
in the absence of added apoproteins and with additions of human CII and
both CII and CIII. Without apoprotein, a pronounced lipolysis of the
triglyceride was recognized by high concentrations of radiolabeled glycerol
and free fatty acid in the perfusate. The removal of an aliquot of hind-end
venous effluent 5 min after adding the labeled triglyceride emulsion to the
arterial inflow demonstrated a brisk lipolysis of the substrate when
incubated outside the perfusion system. The addition of CII protein to the
emulsion before its introduction into the tandem system eliminated
perfusate lipolysis, both within the perfusion system and in incubations of
aliquots withdrawn from the system. Intravascular lipolysis was not seen
with triglyceride emulsions containing both CII and CIH or when an aliquot
of hind-end venous effluent was incubated with triglycerides that had not
been exposed to the perfusion system. The intravascular lipolysis observed
for the [14C]triglyceride added to the tandem system without apoproteins
was associated with relatively greater recoveries of 14C-fatty acyl in
liver, fat, and muscle and relatively greater recoveries of 14CO2 than when
CII alone or both CII and CIII were added with the triglyceride. The
addition of CIII to CII in a 1:1 molar ratio increased the recovery of
14C-fatty acyl in muscle and the recovery as 14CO2.(ABSTRACT TRUNCATED AT
250 WORDS)
