Fig. 1. Ceramide levels in L6 cells induced to differentiate by treatment with Arg8-vasopressin. L6 cells were treated for the time indicated with 10^-7 M AVP alone, 20 µM FB1 alone, in the presence of both compounds or left untreated. Lipids were extracted, and the ceramide mass was measured as described in the Materials and Methods using the DAG kinase method. The data are shown as percent of time 0 value (245±35 ng per mg protein, n=14). (A) Short-term (0-2 hours) AVP effects on ceramide levels. (B) Long-term (3 hours-8 days) AVP effects on ceramide levels. The data are the means ± s.e.m. of three to seven independent measurements. ^*Different from the time 0 value, P<0.05; ^**P<0.01.