A decrease of lipid fluidity of the porcine intestinal brush-border membranes by treatment with malondialdehyde.
The effect of treatment of the porcine intestinal brush-border membranes with malondialdehyde (MDA) on their lipid fluidity was examined using a fluorescence probe, 1,6-diphenyl-1,3,5-hexatriene (DPH). When the membranes were treated with MDA, the fluorescence anisotropy of DPH-labeled membranes increased and the amount of DPH molecules incorporated into the membranes decreased from 3.25 to 2.23 nmol/mg protein. In addition, the response of the fluorescence anisotropy of DPH-labeled membranes to benzyl alcohol, a well-known fluidizer, was markedly suppressed by treatment of the membranes with MDA. These results suggest that treatment of the membranes with MDA causes a decrease of the membrane lipid fluidity. This interpretation was further supported by the increase observed in the fluorescence anisotropy of DPH-labeled liposomes prepared from the extracted lipids of MDA-treated membranes. The results of SDS-polyacrylamide gel electrophoresis suggested that the formation of high-molecular-weight aggregates of the membrane proteins is not involved in the increase of the fluorescence anisotropy of DPH-labeled membranes by treatment with MDA. On the basis of these results, changes in the physical properties of the intestinal brush-border membranes by treatment with MDA are discussed.
Ohyashiki
T
T
Department of Biochemistry, School of Pharmacy, Hokuriku University, Ishikawa.
Sakata
N
N
Matsui
K
K
D000818:Animals; D004161:Diphenylhexatriene; D004591:Electrophoresis, Polyacrylamide Gel; D005454:Fluorescence Polarization; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000166:cytology / Q000187:drug effects*; D008081:Liposomes / Q000378:metabolism; D008315:Malondialdehyde / Q000494:pharmacology*; D008560:Membrane Fluidity / Q000187:drug effects*; D008563:Membrane Lipids / Q000502:physiology*; D008871:Microvilli / Q000187:drug effects / Q000502:physiology; D013050:Spectrometry, Fluorescence; D013552:Swine
D008081:Liposomes; D008563:Membrane Lipids; D004161:Diphenylhexatriene; D008315:Malondialdehyde