Effects of energy-containing nutrients on blood pressure of salt-loaded rats

The present study was performed to investigate whether blood pressure of salt-loaded rats was influenced by the diet. Salt-loaded rats of Wistar strain were fed a high protein high fat diet or a high carbohydrate diet from the age of one month. The experiment was designed so that the intake of sodium chloride was equal in two groups. The body weight on the 14th week of the experiment was 394 +/- 15 g (Mean +/- SE) in the high protein high fat group, and 348 +/- 13 g in the high carbohydrate group. Blood pressure measured weekly by a tail plethysmographic method rose gradually and reached 176 +/- 5 mmHg (Mean +/- SE) on the 14th week in the high carbohydrate group. It was significantly higher than that (127 +/- 7 mmHg) of the high protein high fat group. The pressor responses to angiotensin and noradrenalin were also examined to investigate the mechanism through which salt hypertension was produced more easily by feeding a high carbohydrate diet. These responses to both drugs tended to be greater in the high carbohydrate group, but the differences between the two groups was not significant.