Last update:
11-Nov-2004

OBJECTIVE The purpose of this study was to examine the effects of long-term wheel running on the fatty acid composition of phospholipids and triacylglycerols in rat skeletal and heart muscle.

METHOD Eleven male Wistar rats exercised voluntarily in wheels for eight weeks. Their soleus muscle and heart, and the same organs from fourteen untrained rats were dissected. The fatty acid composition of phospholipids and triacylglycerols was analysed by a combination of thin-layer chromatography and gas chromatography.

RESULTS The soleus muscle exhibited markedly but non-significantly lower triacylglycerols concentrations in the trained animals. The monounsaturated fatty acids of muscle phospholipids were significantly lower in the trained rats. The estimated elongase activity was significantly higher, whereas the Δ⁹-desaturase activity was significantly lower in the trained muscles. The monounsaturated fatty acids of phospholipids were also significantly lower in the trained hearts. The fatty acid composition of phospholipids in the skeletal muscles and the heart adapted to training in a comparable manner, whereas most of the changes in the fatty acid profile of triacylglycerols were tissuedependent. Judging from the magnitude of the effect and the percentage differences between trained and untrained animals, there are many sizeable effects of regular exercise on the fatty acid composition of the skeletal and regular heart muscle of rats.

CONCLUSIONS Long-term wheel running modified the fatty acid profile of phospholipids and triacylglycerols in rat skeletal and heart muscle, and could thus be considered as a modulator of their fatty acid composition.

Key words: Exercise, Fatty acid profile, Heart, Lipid metabolism, Skeletal muscle, Wheel running.