Does PGE1 induce modifications at the membrane level of bone marrow macrophages? A fluorescence study

The effect of prostaglandin E1 (PGE1), and F2 alpha (PGF2 alpha) on the surface membrane configuration of bone marrow macrophages was studied. We measured the fluorescence intensity of membrane bound ANS in prostaglandin pretreated cells. The effect on fluorescence intensity of a blocker of the prostaglandin binding site (SC19220) and inhibitors of prostaglandin synthesis (aspirin, indomethacin, diclophenate, Eicosa 5,8,11,14 tetraynoic acid) also were studied. Enhancement of the fluorescence intensity of bound ANS in cells pretreated with PGE1 indicates a conformational change localized at the membrane surface. That those changes are confined to the cell surface was shown by the failure of PGE1 or PGF2 alpha to alter the fluorescence polarization of bound DPH used as indicator of membrane core viscosity. Our data indicate that PGE1 could act at the surface of the membrane and that its action causes rapid structural perturbation at strategic points in the molecular organization of the membrane of bone marrow macrophages.