Effect of lipid composition on rat liver nuclear membrane fluidity

✍ Scribed by Elisabetta Albi; Maria Letizia Tomassoni; Mariapia Viola-Magni

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 161 KB
• Volume: 15
• Category: Article
• ISSN: 0263-6484
• DOI: 10.1002/(sici)1099-0844(199709)15:3<181::aid-cbf737>3.0.co;2-6

✦ Synopsis

Nuclear membrane ¯uidity is measured in rat liver by use of the ¯uorescence anisotropy of two probes: diphenylhexatriene and its cationic derivative trimethylammonium-diphenylhexatriene. It has been shown that, in 2-monthold rat liver cells, the bilayer surface is less ¯uid than the hydrophobic core. The ¯uidity was higher in 6-day-old rat liver nuclei, in which both the amount of cholesterol and the cholesterol/phospholipid ratio decreased. The in¯uence of the single phospholipids, and in particular of phosphatidylcholine, has been studied by increasing the phosphatidylcholine with a choline base exchange reaction in isolated nuclear membranes. After this reaction, the ¯uorescence anisotropy of the bilayer surface increased, whereas at the hydrophobic core it decreased. Analysis of fatty acid composition shows an increase of phosphatidylcholine unsaturated fatty acids. The results show that the ¯uidity of nuclear membranes changes in relation to the lipid content and to the fatty acid composition. The role of nuclear membrane ¯uidity in cell function is discussed.