Proton Nuclear Magnetic Resonance of Intact Friend Leukemia Cells: Phosphorylcholine Increase during Differentiation

Proton nuclear magnetic resonance of intact Friend leukemia cells was used to analyze their erythroid-like differentiation. The technique, which requires only 10$^{8}$ to 10$^{9}$ cells and approximately 2 minutes for acquisition of each spectrum, demonstrated the occurrence of many signal changes during differentiation. With cell extracts, 64 signals were assigned to 12 amino acids and 19 other intermediary metabolites, and a dramatic signal change was attributed to a fourfold increase in cytoplasmic phosphorylcholines.