STUDIES ON NONESTERIFIED FATTY-ACIDS IN RAT INTESTINAL-CELL MEMBRANES

Lipid composition of total membrane fractions prepared from scraped ra t intestinal mucosa and isolated epithelial cells were compared. Membr anes prepared from mucosa had four times higher nonesterified fatty ac ids (NEFA) as compared to the epithelial cell membranes. Cholesterol a nd phospholipid contents were similar in both the membrane preparation s but triglyceride content was high and di- and monoglyceride were low in epithelial cell membranes as compared to the mucosal membranes. In clusion of p-bromophenacyl bromide, a phospholipase inhibitor, in the intestinal lumen wash solution and homogenizing buffer did not reduce the NEFA content of the scraped mucosal membranes whereas inclusion of diethyl p-nitrophenyl phosphate, a lipase inhibitor reduced it by 40% . These results suggest that NEFA are normal constituent of intestinal cell membranes.