Sucrose does not raise blood pressure in rats maintained on a low salt intake.

Abstract

Diets high in sucrose or fructose have been shown by others to induce a modest elevation of blood pressure in rats. The present experiments were conducted to determine whether the sucrose-induced increase of blood pressure is dependent on the intake of sodium chloride. Four groups of Sprague-Dawley rats were studied: 1) a group maintained on a low salt diet and distilled water (0.45% sodium chloride, no added sucrose), 2) a low salt-high sucrose group (0.45% sodium chloride diet and 7% sucrose in distilled water), 3) a high salt group (4% sodium chloride diet and distilled water), and 4) a high salt-high sucrose group on a diet adjusted dairy to maintain the same high intakes of sodium chloride and sucrose as those of groups 2 and 3. Systolic blood pressures were measured by tail-cuff plethysmography during weeks 1-3 of treatment, and direct mean arterial blood pressures were recorded in conscious animals during week 4. Animals on the high salt diet gained weight more slowly than those on the low salt intake. On the low sodium chloride intake, blood pressures were not affected by high dietary sucrose (group 1 versus 2). In contrast, on the high sodium chloride intake, blood pressures were 10-14 mm Hg higher in sucrosedrinking animals than in water-drinking animals (group 3 versus 4). The increments in blood pressures of the high sodium chloride-high sucrose group were not accompanied by greater increments in body weight compared with the animals on the high sodium chloride intake alone. Sucrose-fed animals exhibited an increase in basal plasma norepinephrine concentrations and increased responsiveness of both norepinephrine and epinephrine to stress (mild electrical foot shock), regardless of the sodium chloride intake. Thus, in the Sprague-Dawley rat, sucrose elevates blood pressure only when adequate salt is present in the diet We hypothesize that a high sucrose intake may activate the sympathetic nervous system but that this activation is effective in elevating blood pressure only when there is a concomitant high intake of sodium chloride. (Hypertension 1993^1:779-785) KEY WORDS • insulin • catecholamines • sympathetic nervous system • hypertension, sodium-dependent S imple carbohydrate feeding (sucrose, glucose, or fructose) increases blood pressure in several normotensive strains of rats, including the Sprague-Dawley rat, the Wistar-Kyoto rat, and the Dahl salt-resistant rat.1 -8 Sucrose feeding also potentiates the development of hypertension in the spontaneously hypertensive rat and in a rat model of adrenal regeneration hypertension.9 " 11 Sucrose-induced increases of blood pressure have been attributed to increased sympathetic nervous system activity. In earlier studies, Hall and Hall 912 reported that addition of sucrose to a 1% NaCl drinking solution augmented the development of both adrenal regeneration hypertension and hypertension after unilateral nephrectomy, and this augmentation was attributed to increased salt consumption in sucrose-drinking rats. More recent evidence, based on indirect blood p...

A high-fructose diet induces insulin resistance but not blood pressure changes in normotensive rats

“…Although several reports indicate fructose as a factor involved in hypertension (4,5,9), several investigators have failed to observe an increase in blood pressure in fructose-fed rats (31,32). These apparently conflicting data have been attributed to differences in the composition of the diets and to variable blood pressure responses to fructose among different ages and strains of normotensive rats (31,32). We observed no significant difference in blood pressure between the highfructose and control groups.…”

“…On the other hand, the AT 1 receptor antagonist losartan and an angiotensin-converting enzyme inhibitor attenuated the magnitude of the blood pressure elevation and improved insulin sensitivity in fructose-fed rats (28)(29)(30). Although several reports indicate fructose as a factor involved in hypertension (4,5,9), several investigators have failed to observe an increase in blood pressure in fructose-fed rats (31,32). These apparently conflicting data have been attributed to differences in the composition of the diets and to variable blood pressure responses to fructose among different ages and strains of normotensive rats (31,32).…”

Factors Involved in the Development of Hypertension Induced by a Low-Protein Diet in Rats with Renal Injury

“…Hyperinsulinemia is frequently associated with sucrose-and fructose-induced hypertension [18], and the increase in sympathetic nervous activity [24] and renal sodium retention caused by hyperinsulinemia [25] might be plausible explanations for the genesis of hypertension. However, insulin resistance or hyperinsulinemia has not been shown in all studies of fructose-or sucrose-induced hypertension [17,[26][27][28]. In this current study, we could find no relationship between the increase in blood pressure and fasting plasma insulin and/or glucose level.…”

Effects of Angiotensin II Receptor Antagonists on Insulin Resistance Syndrome and Leptin in Sucrose-Fed Spontaneously Hypertensive Rats.

“…Hypertension-induced insulin resistance has been demonstrated to accompany increased skeletal muscle vascular resistance (25). Additionally, it has been reported that sucrose feeding increases norepinephrine excretion, turnover, and plasma concentration and enhances sympathetic nerve responses in rats (26,27). Thus sympathetic overactivity may be involved in the pathogenesis of this model, and may be responsible at least in part for the impairment of blood flow to skeletal muscle, which in turn would favor the development of insulin resistance (28).…”