Cardiovascular hypertrophy in angiotensin II-induced hypertension. Influence of losartan and bosentan.

We assessed the role of angiotensin (Ang) II type 1 receptor (AT1) and endo thelin type A and B (ETA & ETB) receptor in cardiovascular hypertrophy asso ciated with angiotensin Ii-induced hypertension (200 ng/kg.min sc for 10 or 17 days). Antagonism of AT1 receptors was obtained by oral administration of losartan (10 or 30 mg/kg.day) and blockade of ETA and ETB receptors was obtained by oral administration of bosentan (30 mg/kg.day). Losartan and bo sentan were administered 24 h before and during the 10 days of angiotensin II (prevention) or they were given after the development of hypertension i. e. from day 10 to 17 of angiotensin II (treatment). Tail-cuff pressure (TCP ) was measured before and at the end of the period of administration of ant agonists. At the end of experiments, cross sectional area (CSA, mm(2)) of t he carotid was measured after perfusion and fixation at 100 mmHg and heart weight index (HWI, mg/g body weight) was determined. Results are mean +/- S EM.