Neonatal changes in fatty acid profile of phospholipids in rat heart muscle.

The fatty acid composition of rat heart phospholipids was examined during the neonatal and postnatal period. The rats were killed on days 1, 7, 14 and 21 after birth and at the ages of 2 and 6 months. The fatty acyl chain composition of the two major phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) changed significantly during the first 2 months. In PC there was a marked and immediate increase in stearic acid, a significant but transient increase in arachidonic acid and late increase in linoleic acid content. In PE there was an immediate increase in stearic acid and docosahexaenoic acid, followed by a late increase in linoleic acid content. The observed alterations in fatty acid composition of heart muscle phospholipids resemble changes induced by repeated administration of norepinephrine and subsequent recovery. Neonatal stress and increased cardiac function play an important role in the modification of the fatty acid composition of rat heart muscle phospholipids during early development.