Incorporation of choline and inositol into phospholipids of isolated bovine oligodendrocyte perikarya.

Oligodendrocyte perikarya have been prepared from fresh and frozen bovine corpus callosum by a slight modification of previously published methods. The properties of the cells which we have obtained appear to be very similar to those previously described in other laboratories. Oligodendrocyte homogenates have been incubated with radioactive choline and inositol in the presence of a number of possible cofactors of phospholipid synthesis. Choline was incorporated into oligodendrocyte phosphatidylcholine both by synthesis de novo and by Ca2+-stimulated base exchange. There was no detectable incorporation of choline into sphingomyelin by either of these routes. Inositol was incorporated into oligodendrocyte phosphatidylinositol by synthesis de novo and by Mn2+-stimulated exchange. Oligodendrocyte homogenates were found to contain sufficient endogenous Ca2+ both to stimulate significant incorporation of choline into lecithin by base exchange and to produce considerable inhibition of lecithin synthesis de novo.