Changes in blood pressure and extracellular fluid with taurine in DOCA-salt rats

The effect of taurine, a sulfur amino acid, on blood pressure and extracellular fluid volume in deoxycorticosterone acetate (DOCA)-salt hypertensive rats was studied. Uninephrectomized rats showed average systolic pressure of 175 +/- 3 mmHg after the 28 days of treatment with DOCA while receiving 1% NaCl solution to drink. The supplementation of 1 and 3% taurine could prevent the development of DOCA-salt hypertension in a dose-related fashion: average pressures on day 28 after these dosages were 126 +/- 2 and 104 +/- 2 mmHg, respectively. Exchangeable body sodium (sodium "space") at week 4 was significantly increased in DOCA-salt rats compared with that of the vehicle-injected control rats. Furthermore, the taurine supplement increased sodium space significantly in the DOCA-salt rats. Overall, there was a negative correlation between the systolic blood pressure and sodium space at week 4 in the taurine-supplemented DOCA-salt rats (r = -0.492, P less than 0.02), although there was a positive correlation between systolic pressure and sodium space in the DOCA-salt rats and the vehicle-injected control rats (r = 0.036, P less than 0.001). The results suggest that taurine loading may attenuate the rise in blood pressure associated with fluid retention during the DOCA-salt treatment and that the fall in blood pressure with its consequence for the renal circulation may be the cause of fluid retention.