SWIMMING CHANGES VASCULAR FATTY-ACID COMPOSITION AND PROSTANOID GENERATION OF RATS

To define the effects of physical activity on vascular fatty acid composition and prostanoid generation, spontaneously hypertensive and normotensive rats were made to swim at 34-35-degrees-C for 5-7 wk. Fatty acids were determined by gas chromatography and prostanoids by high-performance liquid chromatography and electrochemical detection. A characteristic feature of swimming rats was a markedly reduced linoleic acid content in the iliac artery and the aorta; in normotensive swimming rats stearic acid and arachidonic acid contents were increased. These changes could not be attributed to a heat loss during swimming or to depressed growth characteristics. A chemical sympathectomy using guanethidine (60 mg/kg body wt daily) did not prevent the alterations in fatty acid composition. A higher arachidonic acid content was correlated with an increased generation of 6-ketoprostaglandin F1-alpha in the aorta of untreated rats and sympathectomized rats. It is concluded that swimming can alter the vascular fatty acid composition in a manner which results in an increased potential for prostacyclin production.