We aimed to compare the effects of two different vasodilating principles, angiotensin II-receptor blockade and calcium channel blockade, on peripheral insulin-mediated glucose uptake in patients with hypertension and other cardiovascular risk factors. Twenty-one hypertensive patients (11 women and 10 men) with mean age 58.6 years (range 46-75 years), body mass index 29.2 +/- 1.0 kg/m(2) and blood pressure 160 +/- 3/96 +/- 2 mm Hg entered a 4-week run-in period with open-label amlodipine 5 mg. Thereafter they were randomized double-blindly to additional treatment with amlodipine 5 mg or losartan 100 mg. After 8 weeks of treatment, all patients underwent clinical examination and laboratory testing, and 17 of them underwent a hyperinsulinaemic isoglycaemic glucose clamp. After a 4-week open-label wash-out phase, the participants crossed over to the opposite treatment regimen and final examinations with hyperinsulinaemic isoglycaemic glucose clamp after another 8 weeks. Blood pressure was lowered to the same level in both treatment periods. The glucose disposal rate was significantly higher after treatment with losartan 100 mg + amlodipine 5 mg compared to amlodipine 10 mg (4.9 +/- 0.4 vs 4.2 +/- 0.5 mg/kg/min, P = 0.039). Thus our data suggest that angiotensin II-receptor blockade with losartan improves glucose metabolism at the cellular level beyond what can be expected by the vasodilatation and blood pressure reduction alone.