Base stimulation of phospholipid metabolism in neuroblastoma cells. I. Kinetics of incorporation of N-methylated ethanolamine bases.

ABSTRACT

The effects of nitrogen bases on the regulation of phospholipid metabolism in neuroblastoma cell cultures were investigated. An increase in the total cellular phospholipids was observed up to 24 h following plating. Addition of monomethyl- and dimethylethanolamine bases resulted in a stimulation of the synthesis of their corresponding phospholipids. The average rates of synthesis of phosphatidylmonomethyl- and phosphatidyldimethylethanolamine were 0.09 and 0.12 nmol/microgram DNA per h, respectively. The labeling patterns of the various phospholipid species from ortho[32P]phosphate have been determined. They suggest that the synthesis of the analogs proceeded entirely via a phosphate mediated pathway rather than through a base exchange mechanism. A number of distinct patterns for the incorporation of bases into acyl-, alkyl- and alkenyl-containing phosphoglyceride species were indicated. The polar head group composition appeared to be intimately related to the type of bond of the hydrocarbon residue.