The effects of lipid administration on lymphatic apo a-iv and apo b
outputs and on their syntheses.
Nishimura, Masato, Mitsuru Seishima, Hazuki Ohashi, and Akio Noma.
Department of Laboratory Medicine, Gifu University School of
Medicine, 40 Tsukasa-machi, Gifu 500, Japan
APStracts 3:0042G, 1996.
We examined the mesenteric lymphatic and portal venous transport of
triglyceride (TG), free fatty acids (FFA), apo A-IV, apo B in
response to a bolus duodenal infusion of a TG-free control solution,
long-chain (18:1) (LCT), and medium-chain (8:0) (MCT) triglyceride
emulsions in the rat. Additionally, intestinal and hepatic apo A-IV
and B mRNA levels were also measured. Lymph apo A-IV, apo B (B-48),
FFA, and TG output increased after LCT infusion, while only apo A-IV
and FFA outputs increased after MCT infusion. On the other hand,
portal FFA and apo A-IV transports increased at 15 min after MCT
infusion, but not after LCT infusion. Portal TG and apo B transports
were not altered by either MCT or LCT infusion. Jejunal apo A-IV mRNA
was increased after both MCT and LCT infusions. Hepatic apo A-IV mRNA
levels increased only after the MCT infusion. On the contrary,
neither LCT nor MCT had any effect on apo B mRNA levels in intestine
or liver. These results indicate that apo A-IV is regulated by MCT
absorption and fatty acid re-esterification and lipoprotein assembly
are not prerequisite for such regulation. On the contrary, it is
likely that apo B (B-48) participates only in the formation and/or
transport of chylomicrons following LCT absorption.
Received 30 October 1995; accepted in final form 2 February 1996.
APS Manuscript Number G473-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 24 February 96