Induction by SMase of neutral glycosphingolipids of the Gb3 pathway in HDMEC. HDMEC were incubated with SMase (0.067 U/ml) for 0.25, 1, 2, 4, or 24 h. Total neutral glycosphingolipids were extracted and analyzed by HPLC as described in Materials and Methods. The data shown are representative of results from duplicate experiments. GlcCER, glucosylceramide.