Lipid and fatty acid composition of brush border membrane of rat intestine during starvation.

Alterations in the lipid and fatty acid composition of brush border membrane (BBM) of small intestine were studied in well-fed, starved, and refed rats. The ratios of cholesterol/phospholipid (mol/mol), sphingomyelin/phosphatidylcholine (mol/mol), protein/lipid (w/w), and free fatty acids (w/w) decreased whereas the total phospholipid (w/w) ratio and the double-bond index increased in BBM of the intestine of the starved rat compared to that of the well-fed rat. Analyses of fatty acids showed higher percentage of stearic and arachidonic acids whereas oleic and linoleic acids decreased under starvation. The acyl chain of starved rat BBM was less ordered compared with that of well-fed rat BBM. On refeeding, these changes were restored to well-fed levels. The change in membrane state under starvation is associated with alterations in the lipid and fatty acid composition of BBM and may be responsible for functional changes that occur under nutritional stress.