Effects of different antihypertensive treatments and salt stimulation on hemodynamic function and on the development of left ventricular (LV) hypertrophy and fibrosis were investigated in 25 male spontaneously hypertensive rats (SHR) drinking 1% NaCl from month 3 to 6 of age. Eighteen of them received therapy for 2 weeks with either the angiotensin converting enzyme inhibitor captopril (CAP), the b-adrenergic receptor blocker propranolol (PROP) or the calcium-channel antagonist verapamil (VER). Wistar-Kyoto (WKY) rats and untreated SHR served as controls. At 6 months of age, SHR had significantly elevated blood pressure (BP) that was unchanged by salt loading. Relative heart weight was increased in SHR without (3.3), and even more so with salt intake (3.6 vs. 2.4 in WKY). Both in untreated and salt-loaded SHR, mRNA expression of atrial natriuretic factor (ANF) increased 17fold (p<0.001), and collagen I and III mRNA increased 1.7-1.8fold compared to WKY (p<0.01). None of the therapies significantly reduced BP or hypertrophy. However, CAP reduced ANF, collagen I and III mRNA in LV to control level. Less pronounced effects were achieved with VER but not with PROP. These findings emphasize the cardioprotective role of CAP that is not related to its antihypertensive efficacy but might be compromised by elevated salt intake.