Fatty acids and phospholipids of adult and newborn rat hearts and of cultured, beating neonatal rat myocardial cells.

Abstract

AbstractFatty acids and phospholipids of adult and newborn rat hearts and of cultured, neonatal rat heart cells were determined by gas liquid and thin layer chromatographies. In adult heart, the proportion of linoleic acid was higher and that of palmitic acid lower than in newborn hearts or in cultured cells. The relative amounts of linoleic and arachidonic acids in adult heart were affected by the source and amount of dietary fat. In heart cells, after 3 days in culture, the proportion of arachidonic acid resembled that in the newborn and adult rat hearts but showed a gradual and significant decline with age. The gradual shift in fatty acid composition as the cells aged in culture was attributed to outgrowth of mesenchymal cells (fibroblasts and endothelioid cells) characterized by a low relative proportion of arachidonic acid. The amounts of phospholipids in heart cells after 3 days in culture differed from those in the newborn or adult rat hearts. Phosphatidylethanolamine was highest in adult heart (34% of lipid phosphorus) and lowest in cells (26%); lecithin was higher in newborn heart (43%) than in adult heart (37%) or in cells (39%), while sphingomyelin was higher in cells (8%) than in newborn (5%) or adult heart (3%). Phospholipid levels in cultured heart cells were unrelated to those of serum in the growth medium. The absence of a significant change in phospholipid composition after continued incubation of the heart cell cultures for periods up to 3 weeks reflected the major structural role of these lipid components in cell membranes.