The effect of dietary polyunsaturated fat on cation transport and hypertension in the rat.

1. Essential hypertension is associated with increased intracellular sodium in both erythrocytes and leucocytes. Reports in the literature indicate that increasing the level of polyunsaturated fat in the diet reduces hypertension. In the present study, spontaneously hypertensive rats (Wistar-Kyoto, which develop systolic blood pressures in excess of 140 mmHg by 8 weeks of age) were fed on high-fat diets (40% energy derived from fat), the fat being maize oil (high in polyunsaturated fatty acids, PUFA) and coconut oil (low in PUFA). 2. Significantly higher blood pressures developed by 110 d of age in the rats fed on a high-PUFA diet, compared with those fed on the low-PUFA diet. 3. In thymocytes, ouabain-sensitive efflux rate constants were significantly lower in the group fed on the high-PUFA diet. Ouabain-insensitive efflux rate constants were unaffected by diet.