Intestinal triacylglycerol storage pool size changes under differing physiological conditions

Abstract

The intestinal mucosal triacylglycerol storage pool consists of triacylglycerol that is predominantly transported from the intestine via the portal vein rather than in chylomicrons (Am. J. Physiol. 1991. 261: G530-G538). Here we examined the size of the storage pool under varying physiological conditions. Four groups of rats were infused intraduodenally for 4 h. Group A was fasted; group B was infused with trioleoylglycerol, 135 mumol/h; group C was infused with trioleoylglycerol, 135 mumol/h plus phosphatidylcholine, 9 mumol/h; and group D was bile-diverted and infused with trioleoylglycerol, 135 mumol/h. The amount of triacylglycerol in the mucosa increased from groups A to D (A > B > C > D) but the storage pool triacylglycerol was least in groups A and C and greatest in groups B and D. The percentage of trioleoylglycerol in mucosal triacylglycerol was greater in groups B and D than in group A and greater in all groups than the percentage of oleate in the total fatty acids. We conclude that the triacylglycerol storage pool size varies inversely with the efficiency of lymphatic lipid output, which is greatest in rats infused with trioleoylglycerol plus phosphatidylcholine (group C) and least in bile-diverted rats infused with trioleoylglycerol (group D).