Pressor Effects of Fat and Salt in Rats 1

Abstract

Abstract

The role of dietary lipids in the development of salt-induced hypertension was studied. Sprague-Dawley rats were fed a high-fat (HSAT) (5% corn oil-15% coconut oil), a high-carbohydrate (HCARB) (5% corn oil), or a commercial rat diet. Within the HSAT and HCARB groups, subgroups were randomly chosen and the level of salt was varied in the following progression: high salt (HS) (8% NaCl); medium salt (MS) (6% NaCl); and basal salt (BS) (0.15% NaCl). Rats were maintained at each level of salt for 2 weeks. Systolic blood pressure was measured from the tail artery using an electrosphygmomanometer. No significant elevation in blood pressure was demonstrated by rats maintained on the HCARB—BS or commercial laboratory diet during a 6-week experimental period. An intermediate elevation in blood pressure was seen in rats fed the HCARB—HS or HSAT—BS diets. Rats fed the HSAT—HS diet demonstrated the most significant elevation in blood pressure, becoming hypertensive within 1 week of diet introduction. Blood pressure dropped to normotensive levels when the level of salt in the HCARB and HSAT groups was reduced to 6% of the diet. Results from this short-term experiment suggest that the amount of fat in the diet, as well as the level of salt consumed, plays a key role in the regulation of blood pressure in rats.