Release of fatty acids by perfused vascular tissue in normotensive and hypertensive rats

The release of fatty acids from perfused mesenteries of spontaneously hypertensive rats (SHR) and control Wistar-Kyoto rats (WKY) was studied. The release of the prostaglandin precursors dihomogammalinolenic acid, arachidonic acid, and eicosapentaenoic acid was reduced in SHR when compared with age-matched WKY. The release of all other fatty acids detected in the effluent was also reduced. The differences in fatty acid release were evident even when tissue levels of the fatty acids were similar or higher in SHR than in controls. The addition of evening primrose oil and fish oil into the diet partially corrected these defects. Evening primrose oil and fish oil both attenuated increases in blood pressure, but fish oil was more potent than primrose oil. Although both diets reduced vascular reactivity, primrose oil was more effective with lower doses of norepinephrine whereas fish oil blunted the effects of both low and high doses of norepinephrine. The possible mechanisms for the effects of primrose oil and fish oil on vascular reactivity are briefly discussed.