The surface coat of chylomicrons: electron microscopy.

Electron microscope studies were performed on thoracic duct lymph and on washed chylomicrons from dogs fed corn oil. High-resolution electron micrographs showed the presence of a surface coat that differed from the core material and did not resemble a plasma membrane. This was true for both chylomicrons in whole lymph and those that had been subjected to repeated washing. Apparently, the chylomicrons, while passing from the intracellular to the extracellular space, do not acquire their surface coat from pinched off cellular membrane.