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Intestinal absorption of dietary cholesteryl ester is decreased but retinyl ester absorption is normal in carboxyl ester lipase knockout mice.

Abstract：

:Carboxyl ester lipase (CEL; EC 3.1.1.13) hydrolyzes cholesteryl esters and retinyl esters in vitro. In vivo, pancreatic CEL is thought to liberate cholesterol and retinol from their esters prior to absorption in the intestine. CEL is also a major lipase in the breast milk of many mammals, including humans and mice, and is thought to participate in the processing of triglycerides to provide energy for growth and development while the pancreas of the neonate matures. Other suggested roles for CEL include the direct facilitation of the intestinal absorption of free cholesterol and the modification of plasma lipoproteins. Mice with different CEL genotypes [wild type (WT), knockout (CELKO), heterozygote] were generated to study the functions of CEL in a physiological system. Mice grew and developed normally, independent of the CEL genotype of the pup or nursing mother. Consistent with this was the normal absorption of triglyceride in CELKO mice. The absorption of free cholesterol was also not significantly different between CELKO (87 +/- 26%, mean +/- SD) and WT littermates (76 +/- 10%). Compared to WT mice, however, CELKO mice absorbed only about 50% of the cholesterol provided as cholesteryl ester (CE). There was no evidence for the direct intestinal uptake of CE or for intestinal bacterial enzymes that hydrolyze it, suggesting that another enzyme besides CEL can hydrolyze dietary CE in mice. Surprisingly, CELKO and WT mice absorbed similar amounts of retinol provided as retinyl ester (RE). RE hydrolysis, however, was required for absorption, implying that CEL was not the responsible enzyme. The changes in plasma lipid and lipoprotein levels to diets with increasing lipid content were similar in mice of all three CEL genotypes. Overall, the data indicate that in the mouse, other enzymes besides CEL participate in the hydrolysis of dietary cholesteryl esters, retinyl esters, and triglycerides.

journal_name

Biochemistry

journal_title

Biochemistry

authors

Weng W,Li L,van Bennekum AM,Potter SH,Harrison EH,Blaner WS,Breslow JL,Fisher EA

doi

10.1021/bi981679a

subject

Has Abstract

pub_date

1999-03-30 00:00:00

pages

4143-9

issue

eissn

0006-2960

issn

1520-4995

pii

bi981679a

journal_volume

pub_type

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Intestinal absorption of dietary cholesteryl ester is decreased but retinyl ester absorption is normal in carboxyl ester lipase knockout mice.