Antidiuretic and pressor activities of vasopressin analogs with L‐alaninamide and D‐alaninamide substitutions at position 9

Analogs of arginine vasopressin (AVP) and lysine vasopressin (LVP) — with an L‐alaninamide residue or a D‐alaninamide residue replacing the naturally occurring glycinamide in position 9 — lose virtually all pressor activity but retain from 10 to 70% of the antidiuretic activity of their parent hormones. These findings, in conjunction with the data of others on the biological consequences of alterations in positions 7 and 8, show that the antidiuretic receptor will tolerate considerably more structural alteration in the C‐terminal tripeptide “tail” of the vasopressins than will the pressor receptor.