Effect of streptozotocin diabetes on fatty acid content and composition of the heart lipids in the rat.

The aim of the present study was to examine the effect of diabetes on long chain fatty acid content and composition in the heart lipids. The experiments were carried out on male Wistar rats. Diabetes was induced by intravenous administration of streptozotocin. Samples of the blood and the left ventricle were taken. Lipids were extracted and separated into different fractions. The following fractions were examined: free fatty acids, diacylglycerols, triacylglycerols and phospholipids. The fatty acids from each fraction were identified and quantified by means of gas-liquid chromatography. It was found that diabetes resulted in an almost four-fold elevation in the content of the free fatty acid fraction in the heart, whereas the plasma concentration of free fatty acids increased only two-fold. The diabetes induced changes in the content of particular acids in the fraction of free fatty acid in the heart did not reflect changes in their concentration in the plasma. The content of total di- and triacylglycerol fatty acids also markedly increased in diabetes. In both the compounds, the elevation in the content of individual acids, with the exception of myristic and palmitoleic acid reflected roughly the elevation in their concentration in the plasma. There were, however, several differences in the percentage composition of fatty acids between the two groups. In the fraction of phospholipids, the content of myristic, palmitic, stearic and linoleic acids remained stable, whilst the content of palmitoleic acid was reduced and the content of arachidonic acid was elevated. It is concluded that insulin deficiency results in marked changes in the endogenous lipid fatty acid content of the heart. These changes are not directly related to alterations in the supply of individual acids through the plasma.