Cholesterol esterase activity of human intestinal mucosa

Journal Article · Fri Nov 01 04:00:00 EST 1985 · Dig. Dis. Sci.; (United States)

DOI:https://doi.org/10.1007/BF01315603· OSTI ID:6294144

Ponz de Leon, M; Carubbi, F; Di Donato, P; Carulli, N

It has been suggested that cholesterol absorption in humans is dependent on bile acid pool composition and that expansion of the cholic acid pool size is followed by an increase of the absorption values. Similar observations were reported in rats. In the present study, therefore, the authors investigated some general properties of human intestinal cholesterol esterase, with particular emphasis on the effect of bile acids on this enzymatic activity. Twenty-nine segments of small intestine were taken during operations; the enzymatic activity was studied by using mucosal homogenate as a source of enzyme and oleic acid, cholesterol, and UC-labeled cholesterol as substrates. The time-activity relationship was linear within the first two hours; optimal pH for esterification ranged between 5 and 6.2. There was little difference between the esterifying activity of the jejunal and ileal mucosa. Esterification of cholesterol was observed with all the investigated fatty acids but was maximal with oleic acid. Bile acids did not affect cholesterol esterase activity when present in the incubation mixture at 0.1 and 1.0 mM; the enzymatic activity, however, was significantly inhibited when bile acids were added at 20 mM. In conclusion, this study has shown that the human intestinal mucosa possesses a cholesterol esterase activity; at variance with the rat, however, the human enzyme does not seem to be stimulated by trihydroxy bile acids.

• Research Organization: Universita di Modena, Italy
• OSTI ID: 6294144
• Journal Information: Dig. Dis. Sci.; (United States), Journal Name: Dig. Dis. Sci.; (United States) Vol. 11; ISSN DDSCD
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ABSORPTION
ANIMALS
BODY
CARBON 14 COMPOUNDS
CHEMICAL REACTIONS
CHOLESTEROL
DIGESTIVE SYSTEM
ENZYME ACTIVITY
ENZYMES
ESTERASES
ESTERIFICATION
GASTROINTESTINAL TRACT
HYDROLASES
HYDROXY COMPOUNDS
INTESTINAL ABSORPTION
INTESTINES
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
MUCOUS MEMBRANES
ORGANIC COMPOUNDS
ORGANS
RATS
RODENTS
SMALL INTESTINE
STEROIDS
STEROLS
UPTAKE
VERTEBRATES