A high-fructose diet induces insulin resistance but not blood pressure changes in normotensive rats
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Data
2001
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Resumo
Rats fed a high-fructose diet represent an animal model for insulin
resistance and hypertension. We recently showed that a high-fructose
diet containing vegetable oil but a normal sodium/potassium ratio
induced mild insulin resistance with decreased insulin receptor sub-
strate-1 tyrosine phosphorylation in the liver and muscle of normal
rats. In the present study, we examined the mean blood pressure, serum
lipid levels and insulin sensitivity by estimating in vivo insulin activity
using the 15-min intravenous insulin tolerance test (ITT, 0.5 ml of 6 μg
insulin, iv) followed by calculation of the rate constant for plasma
glucose disappearance (K itt ) in male Wistar-Hannover rats (110-130 g)
randomly divided into four diet groups: control, 1:3 sodium/potas-
sium ratio (R Na:K ) diet (C 1:3 R Na:K ); control, 1:1 sodium/potassium
ratio diet (CNa 1:1 R Na:K ); high-fructose, 1:3 sodium/potassium ratio
diet (F 1:3 R Na:K ), and high-fructose, 1:1 sodium/potassium ratio diet
(FNa 1:1 R Na:K ) for 28 days. The change in R Na:K for the control and
high-fructose diets had no effect on insulin sensitivity measured by
ITT. In contrast, the 1:1 R Na:K increased blood pressure in rats receiv-
ing the control and high-fructose diets from 117 ± 3 and 118 ± 3 mmHg
to 141 ± 4 and 132 ± 4 mmHg (P<0.05), respectively. Triacylglycerol
levels were higher in both groups treated with a high-fructose diet
when compared to controls (C 1:3 R Na:K : 1.2 ± 0.1 mmol/l vs F 1:3
R Na:K : 2.3 ± 0.4 mmol/l and CNa 1:1 R Na:K : 1.2 ± 0.2 mmol/l vs FNa 1:1
R Na:K : 2.6 ± 0.4 mmol/l, P<0.05). These data suggest that fructose
alone does not induce hyperinsulinemia or hypertension in rats fed a
normal R Na:K diet, whereas an elevation of sodium in the diet may
contribute to the elevated blood pressure in this animal model.
Descrição
Palavras-chave
High-fructose diet, Insulin resistance, Blood pressure, Plasma cholesterol, Hypertriglyceridemia
Citação
BEZERRA, R. M. N.; UENO, M.; SILVA, M. S.; TAVARES, D. Q.; CARVALHO, C.R.O.; SAAD, M. J. A.; GONTIJO, J. A. R. A high-fructose diet induces insulin resistance but not blood pressue changes in normotensive rats. Brazilian Journal of Medical and Biological Research, Ribeirão Preto, v. 34, n. 9, p. 1155-1160, 2001.