Proteinuric Potentials of Angiotensin II, [des-Asp1]-Angiotensin II, and [des-Asp1, des-Arg2]-Angiotensin II in Rats

To compare proteinuric potentials among angiotensin II (ANG II) and its fragments, [des-Asp1]-angiotensin II (ANG III) and [des-Asp1, des-Arg2]-angiotensin II (ANG IV), the peptide was intravenously infused for 30 min at doses of 0.015, 0.05, 0.15, 0.45 and 1.45 nmol/kg body weight/min. The infusion of ANG II and ANG III increased the fractional clearance of albumin in a dose-dependent manner : most extensively for ANG II, and moderately for ANG III. In contrast, the infusion of ANG IV hardly showed any proteinuric action, even at the maximal dose of 1.45 nmol/kg body weight/min. These results denoted that the cleaving of the N-terminal aspartic acid1 from ANG II weakened the proteinuric action in the glomeruli, and the further cleaving of the N-terminal arginine2 from ANG III led to a complete loss of proteinuric action in the glomeruli.