Fluorescent dansyl derivatives of 3 natural sphingolipids (gangliosides, cerebroside und sphingomyelin) were shown to be readily taken up by culture cells (HeLa-, MDCK- and primary rat brain cells). A part of the incorporated fluorescent sphingolipids remained associated with the cells after incubation in a culture medium containing serum, showing a cellular integration of these lipids. Microscopical studies indicated a localization of incorporated lipids in distinct subcellular regions; whereas dansyl cerebroside densely stained structures suggestive of the cytoskeleton and the actin filament, dansyl sphingomyelin and dansyl gangliosides were primarily associated with the plasma membrane. The findings are consistent with the current views on the arrangement of sphingolipids in animal cells.
