Pancreatic triglyceride lipase deficiency minimally affects dietary fat absorption but dramatically decreases dietary cholesterol absorption in mice

J Biol Chem. 2003 Oct 31;278(44):42899-905. doi: 10.1074/jbc.M303422200. Epub 2003 Aug 12.

Abstract

This study generated pancreatic triglyceride lipase (PTL)-null mice to test the hypothesis that PTL-mediated hydrolysis of dietary triglyceride is necessary for efficient dietary cholesterol absorption. The PTL-/- mice grew normally and displayed similar body weight as their PTL+/+ littermates. Plasma lipid levels between animals of various PTL genotypes were similar when they were maintained on either a basal low fat diet or a western-type high fat/high cholesterol diet. Although the lack of a functional PTL delayed fat absorption during the initial hour of feeding a bolus load of olive oil containing [3H]triolein and [14C]cholesterol, the rate of [3H]triolein absorption was similar between PTL+/+ and PTL-/- mice after the initial 1-h period. Importantly, comparison of fecal fat content revealed similar overall fat absorption efficiency between PTL+/+ and PTL-/- mice. In contrast, the PTL-/- mice displayed significant decrease in both the rate and the amount of cholesterol absorbed after a single meal. The plasma appearance of [14C]cholesterol was found to be 75% lower (p < 0.0005) in PTL-/- mice compared with PTL+/+ mice after 4 h. The total amount of [14C]cholesterol excreted in the feces was 45% higher (p < 0.0004) in PTL-/- mice compared with PTL+/+ mice over a 24-h period. These results indicate that the delayed fat digestion due to PTL deficiency results in a significant reduction in cholesterol absorption, although other enzymes in the digestive tract may compensate for the lack of PTL in PTL-/- mice in fat digestion and absorption.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Absorption
  • Alleles
  • Animals
  • Bile Acids and Salts / metabolism
  • Body Weight
  • Cholesterol / metabolism*
  • DNA, Complementary / metabolism
  • Dietary Fats / metabolism*
  • Fats
  • Feces
  • Genotype
  • Hydrolysis
  • Immunoblotting
  • Lipase / deficiency*
  • Lipase / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Models, Genetic
  • Pancreas / enzymology*
  • Phosphatidylcholines / metabolism
  • Postprandial Period
  • Time Factors

Substances

  • Bile Acids and Salts
  • DNA, Complementary
  • Dietary Fats
  • Fats
  • Phosphatidylcholines
  • Cholesterol
  • Lipase