Deoxycorticosterone Acetate Hypertension in the Sheep

A model of hypertension induced by mineralocoriticoid-excess in the sheep is described. Deoxycorticosterone acetate (DOCA), 100 mg/kg was implanted subcutaneously in adult sheep (n = 13). Before DOCA administration, and for 30 days thereafter, mean arterial blood pressure (MAP), plasma electrolyte levels, plasma renin activities, water and electrolyte intakes and urinary outputs were monitored. Within 72 h after DOCA implantation MAP had risen from a control value of 83.0 +/- 2.0 to 93.0 to 3.0 mmHg, MAP stabilized at 114.0 +/- 3.0 mmHg three weeks later. Water intake had increased significantly by the 4th post-implant day and reached a maximum of 10.0 +/- 1.2 l/day by the third week. The following biochemical changes were significant within 24 h after DOCA implantation; (1) plasma potassium fell from 4.4 +/- 0.1 to 3.42 +/- 0.13 mEq/l; (2) plasma sodium rose from 144.4 +/- 0.6 to 147.0 +/- 0.4 mEq/l; (3) plasma renin activity fell from 1.29 +/- 0.42 to 0.13 +/- 0.08 ng ANG l/ml/h. The rapidity of onset and reversal of arterial pressure elevation in this model render it a useful tool in providing insight into the mechanism responsible for this form of hypertension.