A simple and sensitive determination for plasmalogen lysophosphatidylethanolamine in rabbit platelets

Plasmalogen lysophosphatidylethanolamine (LPE) in rabbit platelets was quantitatively determined as glycero-3-phosphorylethanolamine (GPE) after treatment with 5% trichloroacetic acid at 20 degrees C for two hours. GPE was measured directly using a high performance liquid chromatography with monitoring the fluorescence of o-phthaldialdehyde/2-mercaptoethanol adducts. The assay was sensitive to 50 pmol of plasmalogen LPE and was linear over a 200-fold concentration range. While, 1-acyl LPE and phosphatidylethanolamine from bovine brain (containing about 50% plasmalogen) were hardly cleaved to GPE under the same conditions. These procedures were specific for plasmalogen LPE, and simpler and more sensitive in comparison with conventional analytical methods, e.g., two-dimensional thin layer chromatography with subsequent phosphorus assay. Employing the present method, plasmalogen LPE was found to increase rapidly and to decrease subsequently when rabbit platelets were stimulated by thrombin.