Moexiprilat, an active metabolite of the prodrug moexipril formed through side chain ester hydrolysis in vivo, functions as an angiotensin-converting enzyme (ACE; IC50 = 2.1 nM) inhibitor. At a concentration of 10 nM, it inhibits the proliferation of primary neonatal rat cardiac fibroblasts stimulated by estrone or angiotensin II. Furthermore, when given at a daily dosage of 50 mg/kg, moexiprilat reduces mean arterial blood pressure and elevates levels of atrial natriuretic peptide, an indicator of hypertension, in ovariectomized mice.