Glucosylceramide in 9 V/null and 4L mice. A: LC-MS/MS analyses showed an age dependent progressive accumulation of glucosylceramide in the lung of 9 V/null mice: 6-fold, 28- to 33-fold, and 40-fold greater than WT at 4, 12-28, and 52 wk, respectively. In the 4L lung, there was ~3-fold increase by 4 to 52 wk. B: Similar, progressive accumulation of liver glucosylceramide: 5-fold, 15-fold, 32-fold, and 46-fold greater than WT at 12, 18, 28, or 52 wk, respectively. Glucosylceramide levels in the liver of 4L were 2-fold increased over the WT.