The phospholipids from murine mastocytoma FMA3 and P-815 clone cells were quantitatively analyzed, and the major glycerophospholipids were examined for their fatty acyl chain distribution. In these cells, the content of histamine was less than 1/100 of normal mouse mast cells, and FMA3 cells had 1.5-fold as much histamine content as P-815 cells. The predominant phospholipid species of both mastocytoma FMA3 and P-815 were choline-containing glycerophospholipids (48%) and ethanolamine-containing glycerophospholipids (29%). The remaining minor constituents were sphingomyelin (6%, 7%), phosphatidylinositol (7%, 5%), phosphatidylserine (2%, 5%), cardiolipin (4%, 3%), and phosphatidic acid (2%, 1% for FMA3 and P-815, respectively). The choline-containing glycerophospholipids consisted of high amounts of 1-O-alkyl-2-acyl type (31%, 25%) and 1,2-diacyl type (63%, 66%) and a smaller amount of 1-O-alk-1'-enyl-2-acyl type (7%, 8%). In contrast, ethanolamine-containing glycerophospholipids were characterized by high contents of 1-O-alk-1'-enyl-2-acyl type (36%, 31%) and 1,2-diacyl type (55%, 58%), and a lower level of 1-O-alkyl-2-acyl type (12% and 11% for FMA3 and P-815, respectively). Unlike choline-containing glycerophospholipids and sphingomyelin that were rich in palmitic acid, ethanolamine-containing glycerophospholipids, phosphatidylserine and phosphatidylinositol showed a high proportion of stearic acid in the overall fatty acid composition. The content of arachidonic acid was highest in phosphatidylinositol. Sphingomyelin had a large amount of long chain and polyunsaturated fatty acids. In both choline- and ethanolamine-containing glycerophospholipids, the predominant fatty acids in the sn-1-position were palmitic, stearic, and oleic acid.(ABSTRACT TRUNCATED AT 250 WORDS)