Selective pharmacological effects of triprolyl and pentasarcosyl angiotensin II.

Among the various biological effects of angiotensin II (AII), both pressor activity and aldosterone stimulation appear to be mediated by functionally different receptors. With this in mind, we compared pressor and aldosterone-stimulating activities of AII with those of triprolyl [(Pro)3] AII and pentasarcosyl [(Sar)5] AII. In conscious male Wistar rats (Pro)3 AII and (Sar)5 AII produced 48 and 46% of the pressor activity of AII. After intravenous infusion (conscious unrestrained rats, 125 pmol/kg/min for 30 min), plasma aldosterone concentrations were not significantly different from those of control rats which were infused with saline. However, when the rats were infused with AII (125 pmol/kg/min for 30 min), plasma aldosterone concentrations increased significantly (1,306 +/- 80 pg/ml). This study indicates that (Pro)3 AII and (Sar)5 AII may prove to be useful tools to elucidate biological actions of AII.