Figure 7.

Bovine serum albumin (BSA) inhibits S1P uptake.A and B, HUVECs (A) and MEDEP-E14 cells (B) were labeled with 0.2 μCi [³²P]Pi or 0.2 μCi [³²P]S1P for 3 h in the presence of 0, 0.1, 1, or 10% BSA. Lipids were extracted and separated by TLC, and [³²P]PE levels were quantified using an imaging analyzer BAS2500. Values represent the means ± SD of the radioactivity relative to that in [³²P]Pi-labeled cells without BSA treatment from three independent experiments (∗∗p < 0.01; Tukey's test). HUVEC, human umbilical vein endothelial cell; MEDEP, mouse ES cell-derived erythroid progenitor line; PE, phosphatidylethanolamine; Pi, orthophosphoric acid; S1P, sphingosine-1-phosphate.