Regulation of phospholipid methylation
5.1. Regulation by substrate availability
Probably the first report to examine the regulation of PE methylation
demonstrated that incubation of rat primary hepatocytes with
0.2 mM methionine doubled the conversion of PE to PC [4,33]. Subsequently,
experiments showed that increasing the concentration
of ethanolamine to 0.5 mM from 0.2 mM in the medium of primary
hepatocytes doubled the amount of PE in the cells and also doubled
the methylation of PE [34]. Related experiments a decade later with
rat liver microsomes supported the finding that an increase in the
concentration of PE stimulates PE methylation [35]. Furthermore,
it appears that only PE newly-made via the CDP-ethanolamine pathway
is converted to PC [30].