A rapid and sensitive method to measure secretion of sphingosine-1-phosphate.

The serum-borne, bioactive sphingolipid mediator, sphingosine-1-phosphate (S1P), regulates numerous important physiological and pathological processes, mainly acting through specific cell surface G-protein-coupled receptors. Although many mammalian cells can produce S1P, there is little information as to how it is secreted to reach its receptors. Progress in elucidating this mechanism has been hampered by the difficulty of measuring very low levels of S1P. This chapter describes a simple, rapid method to measure S1P export from cells. It also discusses the current knowledge of how S1P is exported out of cells and its physiological significance.