Increased activity of a phospholipid base-exchange system by the differentiation of neoplastic cells from the nervous system.

The activity of a base-exchange enzyme system, specific for the polar head-groups of brain phospholipids, was measured in both C 1300 mouse neuroblastoma (clone 41A3) and human glioma 138 MG cell lines. This base-exchange is thought to occur between free nitrogenous bases and membrane-bound phospholipids. The incorporation of free 14C-labeled ethanolamine and L-serine was determined in undifferentiated and morphologically differentiated cells. Both cell lines showed a significant increase in ethanolamine and L-serine incorporation upon differentiation.