Sobrecarga salinas cronica em ratos Wistar eleva a pressão arterial e aumenta o metabolismo da glicose, sem modificar a sensibilidade a insulina / Sobrecarga salina cronica em ratos wistar eleva a pressao arterial e aumenta o metabolismo da glicose, sem modificar a sensibilidade a insulina

AUTOR(ES)
DATA DE PUBLICAÇÃO

1995

RESUMO

During the human aging process, it is observed an increase in arterial pressure and a higher prevalence of carbohydrate metabolism disorders, like insulin resistance on glucose uptake, glucose intolerance, and diabetes mellitus type II. It is an open question if there is a cause-effect association between hypertension and insulin resistance or if there is only an eventual concomitance between the two phenomena, with potencial amplifier action of each other. On the other hand, as salt takes part in the blood pressure increase along lifetime, it is important to know its role on insulin sensitivity during aging. The purpose of the present study was to evaluate the salt effect on arterial pressure, glucose metabolism, and insulin resistance in rats during aging. Male Wistar rats were fed, from weaning, with a low (NaCl 0,15%) or high salt (NaCl 7,94%) diet until they were 72 weeks old. A subgroup of animals on each diet had their diets inverted after the 48th week of age. In young and old animals, arterial blood pressure, weight, kidney and left ventricular mass were measured; intravenous glucose tolerance test, insulin tolerance test, in vitro studies (glucose uptake and metabolism, and insulin receptors density) were evaluated. Blood pressure was increased on high salt diet during the whole study (p=0.017), without a time effect (p=0.994). The weight was higher on salt restriction, rising during the aging process (p<0,001). Kidney and left ventricular mass were higher on high salt diet. Blood pressure, kidney and left ventricular mass increases were reverted with the inversion of diets. Lower insulin levels were observed on high salt diet during intravenous glucose tolerance test. However, insulin sensitivity was the same on both diets in young (noticed in the isolated adipocytes study) and also in old rats (noticed in the insulin tolerance test). The glucose uptake and metabolism were higher on high salt diet due to an insulin-independent glucose uptake. Insulin receptor density was higher also on high salt diet, perhaps by an upregulation due to the lower insulin levels. Along aging, glucose tolerance decreased on both diets, but it was higher in the group under salt overload, perhaps due to the higher basal glucose uptake in this group. In conclusion, higher blood pressure on high salt diet, with no differences of insulin sensitivity between high and low salt diet, were observed either in young or old rats. In this model, therefore, there was no association between blood pressure levels and insulin resistance. A higher insulinindependent glucose uptake was associated to salt overload, what was not previosly reported.

ASSUNTO(S)

nefrologia arterial pressure ratos wistar salt diet insulina insulin salt glicose glucose wistar rats dieta hipersódica neprhology pressão arterial sal

ACESSO AO ARTIGO

Documentos Relacionados