Des-Leu angiotensin I: biosynthesis and drinking response

The crude rat and bovine synaptosomal lysate from brain can hydrolyze angiotensin I (AI) to des-Leu angiotensin I (AI-dL) and no further. This cytosolic enzyme has a specificity for angiotensin-related sequences, R-His-Pro-Phe-His-Leu and therefore named angiotensin-related carboxypeptidase (ARC). These studies led to the biosynthesis and purification of AI-dL in order to determine if it can provoke a drinking response. This nonapeptide is a potent dipsogen when injected into the cerebroventricles of rats. The drinking response probably requires a second hydrolysis to angiotensin II (AII) since both captopril and saralasin can inhibit this response.