FIGURE 7.
Sphingolipid profile of Sgpp1−/− keratinocytes. Primary keratinocytes from skin of 1-day-old Sgpp1+/+ and Sgpp1−/− mice were grown in low Ca2+ media for 3–4 days. The sphingolipid profile of each culture was determined by HPLC-tandem MS. Levels of sphingosine, S1P, and dihydro-S1P (A), total ceramide (B), and individual ceramide fatty acid chain species (C) were determined. Values are expressed as picomoles of sphingolipid per nmol of inorganic phosphorous (Pi). Bars represent mean values ± S.D. n = 5 for each genotype. Student's t test; *, p < 0.05; **, p < 0.01; ***, p < 0.001. ns, not significant.