Formation of ceramide in ethanol-treated astrocytes: time course. Astrocytes were labeled with [3H]-serine for 72 hours, washed and treated with ethanol (0.3 %, v/v) in serum-free medium. At the indicated time points, the cells were extracted with methanol/chloroform (2:1), lipid extracts were separated by TLC, and radioactivity associated with [3H]-ceramide and [3H]-sphingomyelin was determined by liquid scintillation counting. Data (N = 3–7) are means ± S.E.M. and are expressed as [%] ceramide/sphingomyelin. Statistics: ANOVA, F1,53 = 2.28, p = 0.02. *, p < 0.05 vs. control at time zero (Dunnett's post test).