Control of spontaneous and deoxycorticosterone-salt hypertension and polyuria by nitrendipine pellets

Weekly subcutaneous implantation of 25-mg nitrendipine pellets prevented onset of both spontaneous and deoxycorticosterone-salt hypertension in rats. Discontinuance of implantation led to reappearance of hypertension after about 2 weeks in the former and led to rising though still normotensive pressures after about 3 weeks in the latter. A new implant caused blood pressures in both to drop within a day or two to normotensive levels in the case of spontaneously hypertensive rats. Nitrendipine prevented cardiac hypertrophy in steroid hypertensive rats, but not in spontaneous hypertensives. A nitrendipine pellet given 1 day before or a 30 mg/kg injection given 1 h prior to the administration of a water, Na+, and K+ load, prevented the diabetes insipidus-like syndrome resulting from deoxycorticosterone-salt treatment, and lowered sodium but not potassium excretion. Nitrendipine did not affect steroid-induced hypernatremia and hypokalemia.