Vasopressin and oxytocin analogs with interchanged sequence of amino acids in positions 7 and 8. synthesis and biological effects

Abstract

p-Toluenesulfonyl-S-benzylcysteinyl-tyrosyl-phenylalanyl-glutaminyl-asparaginyl-S-benzylcysteinyl-NG-p-toluenesulfanylarginyl-prolyl-glycineamide (I) and S-benzylcysteinyl-tyrosyl-isoleucyl-glutaminyl-asparaginyl-S-benzylcysteinyl-leucyl-prolyl-glycine amide (III) were prepared by solid phase synthesis. After removal of the protecting groups, closure of the disulfide ring, and purification by continuous free-flow electrophoresis [arginine7, proline8]vasopressin (II) and [leucine7, proline8]oxytocin (IV) were obtained. The antidiuretic effect of II is markedly higher than its pressor effect; IV possesses c. 6% of the uterotonic and c. 10% of the galactogogous effect of oxytocin.