Abstract des Autors

The blood-borne free fatty acids are the main energy source for the heart. The heart contains also a sizeable pool of endogenous long chain fatty acids. They are esterified, mostly into phospholipids and triacylglycerols, and only a small fraction remains unesterified. The aim of the present study was to examine the effect of exercise of moderate intensity (30 min, or till exhaustion) on fatty acid content and composition in different lipid fractions of the rat heart. The experiments were carried out on male Wistar rats. They were forced to run on a treadmill set at +10ø with a speed of 1200 m/h. The samples of the left ventricle and blood were taken at rest, after 30 min exercise and at exhaustion (201+/-23 min). Lipids were extracted with chloroform/methanol and separated into four fractions (free fatty acids, di-, and triacylglycerols, and phospholipids) by means of thin-layer chromatography. The fatty acids of each fraction were identified and quantified by means of gas- liquid chromatography. It was found that the total content of free fatty acid fraction is elevated both after 30 min exercise and at exhaustion. The changes in the content of individual acids in this fraction did not reflect those in the plasma. The content of di-, and triacylglycerol fatty acids increased, whereas the content of phospholipid fatty acids decreased at exhaustion. Again, in most cases changes in individual fatty acids content in particular lipids were not directly related to changes in the respective free fatty acid concentration in the plasma. It is concluded that exercise of moderate intensity affects long-chain fatty acid content and composition in different lipid fractions in the heart. Verf.-Referat