UNUSUAL EFFECTS OF SOME VEGETABLE-OILS ON THE SURVIVAL-TIME OF STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS

Preliminary experiments have shown that a diet containing 10% rapeseed oil (low-erucic acid) markedly shortens the survival time of stroke-p rone spontaneously hypertensive (SHRSP) rats under 1% NaCl loading as compared with diets containing perilla oil or soybean oil. High-oleate safflower oil and high-oleate sunflower oil were found to have surviv al time-shortening activities comparable to that of rapeseed oil; oliv e oil had slightly less activity. A mixture was made of soybean oil, p erilla oil, and triolein partially purified from high-oleate sunflower oil to adjust the fatty acid composition to that of rapeseed oil. The survival time of this triolein/mixed oil group was between those of t he rapeseed oil and soybean oil groups. When 1% NaCl was replaced with tap water, the survival time was prolonged by similar to 80%. Under t hese conditions, the rapeseed oil and evening primrose oil shortened t he survival time by similar to 40% as compared with n-3 fatty acid-ric h perilla and fish oil; lard, soybean oil, and safflower oil with rela tively high n-6/n-3 ratios shortened the survival time by roughly 10%. The observed unusual survival time-shortening activities of some vege table oils (rapeseed, high-oleate safflower, high-oleate sunflower, ol ive, and evening primrose oil) may not be due to their unique fatty ac id compositions, but these results suggest that these vegetable oils c ontain factor(s) which are detrimental to SHRSP rats.