title: Cholesterol esterase accelerates intestinal cholesterol absorption.
abstract: Mechanisms of acceleration of cholesterol absorption by cholesterol esterase were investigated in various experimental conditions. Lymphatic recovery of cholesterol intubated as a micellar solution containing phosphatidylcholine (PC) into the duodenum was enhanced by the co-administration of cholesterol esterase in rats drained of bile and pancreatic juice. However, no accelerated incorporation was observed when cholesterol was solubilized in PC-depleted micelles. Cholesterol esterase dose-dependently accelerated the incorporation of cholesterol into differentiated Caco-2 cells, only when cholesterol was solubilized in PC-containing micelles. The accelerated incorporation of cholesterol into Caco-2 cells by cholesterol esterase disappeared when the enzyme was preincubated with a suicide inhibitor of cholesterol esterase. Cholesterol esterase has an activity as phospholipase A(2). When 10% of PC in bile salt micelles was replaced by lysophosphatidylcholine (lysoPC), the incorporation of cholesterol into Caco-2 cells was significantly accelerated. Cholesterol esterase enhanced the incorporation of micellar cholesterol into brush border membranes prepared from the rat jejunum. The addition of cholesterol esterase to bile salt micelles accelerated the release of micellar cholesterol in a dose-dependent manner, only when the micelles contained PC. These observations strongly suggest that cholesterol esterase hydrolyzes PC in bile salt micelles and thereby, accelerating the release of cholesterol from bile salt micelles. This may be a major cause of the acceleration of cholesterol absorption by cholesterol esterase.
authors.affiliation: Laboratory of Nutrition Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka, Japan. iikeda@agr.kyushu-u.ac.jp
authors.forename: Ikuo
authors.initials: I
authors.lastname: Ikeda
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Matsuoka
authors.forename: Tadateru
authors.initials: T
authors.lastname: Hamada
authors.forename: Kosuke
authors.initials: K
authors.lastname: Mitsui
authors.forename: Sachiko
authors.initials: S
authors.lastname: Imabayashi
authors.forename: Akira
authors.initials: A
authors.lastname: Uchino
authors.forename: Masao
authors.initials: M
authors.lastname: Sato
authors.forename: Eiichi
authors.initials: E
authors.lastname: Kuwano
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Itamura
authors.forename: Koji
authors.initials: K
authors.lastname: Yamada
authors.forename: Kazunari
authors.initials: K
authors.lastname: Tanaka
authors.forename: Katsumi
authors.initials: K
authors.lastname: Imaizumi
mesh_terms: D000818:Animals; D018938:Caco-2 Cells; D002784:Cholesterol / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004951:Esterification / Q000187:drug effects; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000378:metabolism; D008297:Male; D008823:Micelles; D008871:Microvilli / Q000378:metabolism; D010713:Phosphatidylcholines / Q000494:pharmacology*; D011753:Pyrones / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D002787:Sterol Esterase / Q000494:pharmacology*; D014304:Triolein
chemical_list: D004791:Enzyme Inhibitors; D008823:Micelles; D010713:Phosphatidylcholines; D011753:Pyrones; D014304:Triolein; C037903:3-benzyl-6-chloro-2-pyrone; D002784:Cholesterol; D002787:Sterol Esterase