Incorporation of choline, serine, ethanolamine and inositol into phospholipids of isolated rat mast cells.

The incorporation of labelled phospholipid precursors, [Me-14C]-choline, L-[3(-14)C]-serine, [2(-14)C]-ethanolamine and [2(-3)H]-myoinositol into the phospholipids of isolated rat mast cells was studied. The label from the different precursors were found to be essentially associated with compounds with the t.1.c.-motility of the respective phospholipids. Whereas the incorporation of [Me(-14)c]-choline and L-[3(-14)C]-serine showed evidence of saturation the incorporation of [2(-14)C]-ethanolamine was linear with time (2 h) and it was not saturated by increasing the concentration from 0.07 mM to 2.07 mM. The incorporation of [2(-3)H]-myoinositol was stimulated by Ca2+ (1 mM) or Mg2+ (1 mM), while the incorporation of the other precursors was stimulated only in the presence of both Ca2+ and Mg2+ (1 mM). Antimycin A (1muM), an inhibitor of the respiratory chain, significantly ingibited the incorporation of [Me(-14)c]-choline, L-[3(-14)C]-serine and [2(-3)H]-myoinositol but not that of [2(-14)C]-ethanolamine. The experimental system used might be a useful model for studies on the turnover of membrane phospholipids during histamine release.