SUGAR-INDUCED HYPERTENSION IN SPRAGUE-DAWLEY RATS

Male Sprague-Dawley rats were fed either conventional rat chow, or a diet in which vegetable starch was replaced with either glucose or sucrose for two weeks. At the end of this period, measurements were made of weight, blood pressure, and plasma glucose, insulin, and triglyceride concentrations. The average weight gain over the dietary period was approximately 75 g, and did not vary between the three groups. Mean (+/- SEM) blood pressure remained stable in the rats fed conventional chow (124 +/- 2 to 127 +/- 3 mm Hg), but increased significantly in rats fed the glucose-enriched diet (122 +/- 1 to 134 +/- 2 mm Hg, P < .02, compared to chow-fed rats). The increase in blood pressure was even greater in rats fed the sucrose-enriched diet (122 +/- 2 to 144 +/- 2), and was significantly greater (P < .005) than in rats fed either conventional chow or the glucose-enriched diet. Plasma glucose concentrations did not change in any of the groups, but plasma insulin concentration approximately doubled in rats fed either the glucose-enriched or sucrose-enriched diets. Finally, plasma triglyceride concentrations also were significantly higher (P < .002) in both glucose-fed and sucrose-fed rats than in the control group. However, the increase was greatest in the sucrose-fed rats, and was significantly higher than in rats fed the glucose-enriched diet (P < .002). Thus, substituting either glucose or sucrose for the vegetable starch usually present in conventional rat chow leads to significant increases in blood pressure and plasma insulin and triglyceride concentrations in Sprague-Dawley rats. These effects were greatest when rats were fed the sucrose-enriched diet, with glucose-fed rats having an intermediate response. These results indicate that feeding simple sugars to a nongenetic rat model of hypertension can lead to changes in blood pressure and plasma insulin and triglyceride concentrations similar to those reported to occur in human beings with hypertension.