Nachweis, dass die Substitution in Positionen 3 und 8 im Arginin Vasotocin ([8-Arginin]-Oxytocin) selektive Veränderungen verschiedener biologischer Aktivitäten hervorruft, was am Modell der Oxytocinkonformation diskutiert wird.
Supported in part by USPHS grant No. AM-13567.
Neurohypophyseal hormone analogs are denoted in accordance with IUPAC-IUB Tentative Rules on Biochemical Nomenclature, Biochemistry6, 362 (1967) and J. biol. Chem.247, 977 (1972). All optically active amino acids are of thel-configuration unless otherwise noted. Arginine vasopressin, [8-arginine]vasopressin; lysine vasopressin, [8-lysine]vasopressin; AVT, arginine vasotocin, [8-arginine]oxytocin; Mpr, 
-mercaptopropionic acid.
Acknowledgment. We thank Dr.Klaus Lübke, Schering AG, West Germany, for generously supplying us with the hormone analogs.