Isolated rabbit enterocytes as a model cell system for investigations of chylomicron assembly and secretion.

A method is described for the isolation of viable enterocytes from rabbit small intestine. The procedure can also be used to isolate populations of epithelial cells from the crypt/villus gradient. The isolated enterocytes synthesized and secreted apoB-48 and triacylglycerol in particles of the density of chylomicrons. Secretion was stimulated by addition of bile salt/lipid micelles. Pulse-chase experiments demonstrated that newly synthesized apoB-48 is degraded intracellularly and that degradation is inhibited by provision of lipid micelles, suggesting that regulation of chylomicron assembly and secretion is broadly similar to that of very low density lipoprotein assembly in hepatocytes. This procedure for preparation of isolated enterocytes will provide a useful model system for investigation of the molecular details of chylomicron assembly.