SUGAR-INDUCED BLOOD-PRESSURE ELEVATIONS OVER THE LIFE-SPAN OF 3 SUBSTRAINS OF WISTAR RATS

Objective: Since the majority of studies concerned with sugar-induced blood pressure elevation have principally been short-term, the present investigation followed the effects of heavy sucrose ingestion on syst olic blood pressure (SEP) and related parameters over the lifespan of three substrains of Wistar rats.Methods: Two hundred twenty-five rats( 75 spontaneously hypertensive rats (SHR), 75 Wistar Kyoto rats (WKY), 75 Munich Wistar rats (WAM)) were given one of five diets. The baselin e diet in terms of calories derived 32% from sucrose. 33% from protein , and 35% from fat. The remaining four diets derived their calories as follows: a high sugar-lbw protein diet-52% of calories from sucrose, 15% from protein, and 33% from fat; a high sugar-low fat diet-53% of c alories from sucrase, 37% from protein, and 10% from fat; a low sugar- high protein diet-11% calories from sucrose, 56% from protein, and 33% from fat, and a low sugar-high fat-13% of calories from sucrose, 32% from protein, and 55% from fat. Results: All substrains showed the hig hest systolic blood pressure when ingesting the two diets highest in s ucrose, The highest sugar-induced SEP elevation, which remained over t he lifespan of all substrains, was found in SHR. WKY had an intermedia te elevation. WAM showed the lowest responses, although the average el evation of 6-8; mm Hg was statistically significant. The following par ameters could nor be correlated with long-term elevation of SEP: body weight, catecholamine excretion, renal function, and plasma renin acti vity. Only insulin concentrations correlated: insulin concentrations w ere consistently higher To the two groups of WKY and WAM consuming the high sucrose diets, Conclusions: High dietary sucrose can chronically increase SEP in three substrains of Wistar rats. Increased concentrat ions of circulating insulin were found in WKY and WAM suggesting that the glucose/insulin system was involved. at least in these two substra ins, in the maintenance of high SEP levels during chronic, heavy sugar ingestion.