title: Permeability properties of apical and basolateral membranes of the guinea pig caecal and colonic epithelia for short-chain fatty acids.
abstract: Unidirectional fluxes of short-chain fatty acids (SCFA) indicated marked segmental differences in the permeability of apical and basolateral membranes. The aim of our study was to prove these differences in membrane permeability for a lipid-soluble substance and to understand the factors affecting these differences. Apical and basolateral membrane fractions from guinea pig caecal and colonic epithelia were isolated. Membrane compositions were determined and the permeability of membrane vesicles for the protonated SCFA was measured in a stopped-flow device. Native vesicles from apical membranes of the caecum and proximal colon have a much lower permeability than the corresponding vesicles from the basolateral membranes. For the distal colon, membrane permeabilities of native apical and basolateral vesicles are similar. In vesicles prepared from lipid extracts, the permeabilities for the protonated SCFA are negatively correlated to cholesterol content, whereas no such correlation was observed in native vesicles. Our findings confirm that the apical membrane in the caecum and proximal colon of guinea pig is an effective barrier against a rapid diffusion of small lipid-soluble substances such as SCFAH. Besides cholesterol and membrane proteins, there are further factors that contribute to this barrier property.
authors.affiliation: Department of Physiological Chemistry, School of Veterinary Medicine Hannover, Bünteweg 17, D-30559, Hanover, Germany.
authors.forename: Roger
authors.initials: R
authors.lastname: Busche
authors.forename: Joachim
authors.initials: J
authors.lastname: Dittmann
authors.forename: Hans-Dieter
authors.initials: HD
authors.lastname: Meyer zu Düttingdorf
authors.forename: Uwe
authors.initials: U
authors.lastname: Glockenthör
authors.forename: Wolfgang
authors.initials: W
authors.lastname: von Engelhardt
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Sallmann
mesh_terms: D000818:Animals; D002432:Cecum / Q000737:chemistry / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D002463:Cell Membrane Permeability; D002784:Cholesterol / Q000032:analysis; D003106:Colon / Q000737:chemistry / Q000378:metabolism*; D004848:Epithelium / Q000737:chemistry / Q000378:metabolism; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D006168:Guinea Pigs; D008051:Lipid Bilayers / Q000737:chemistry; D008297:Male; D008565:Membrane Proteins / Q000032:analysis
chemical_list: D005227:Fatty Acids; D008051:Lipid Bilayers; D008565:Membrane Proteins; D002784:Cholesterol