Effects of acute myocardial infarction and of noradrenaline infusion on fatty acid composition of serum lipids

Abstract

Changes in the fatty acid composition of serum free fatty acids (FFA), triglycerides, cholesterol esters and phospholipids have been studied during the first 3 days after acute myocardial infarction and after noradrenaline infusion.When compared with healthy subjects or patients with a long history of ischaemic heart disease, the only significant change in patients after acute myocardial infarction was elevated oleic acid in the FFA fraction. The composition of triglyceride, cholesteryl and phospholipid fatty acids was not consistently altered.Immediately after a 15-min infusion of noradrenaline, serum FFA were raised and the percentage of free oleic acid and linoleic acids were increased; there was a significant decrease in the percentages of stearic and palmitic acid. Hyperlipidaemic patients did not show any increase in free linoleic acid in response to noradrenaline.In the healthy subjects there were increases in the percentages of triglyceride oleate and of cholesteryl and phospholipid arachidonate. The total phospholipid concentrations and the percentage of phospholipid palmitate decreased. In general, less significant changes were seen in hyperlipidaemic patients given noradrenaline. Changes in composition and concentration during the time of fatty acid mobilisation by noradrenaline suggest an interrelationship between the mechanism of fatty acid mobilisation and metabolism of serum phospholipids. Thus, the increased fatty acid mobilisation which follows myocardial infarction is associated with fewer changes in the composition, particularly of esterified fatty acids, than immediately after noradrenaline infusion.