| 摘要 |
Polypeptides having formula (I), wherein X is hydrogen or -NH2; Y and Z are independently sulfur or CH2; R<1> and R<2> are hydrogen, methyl, cyclopentamethylene or an alkyl group having 1 to 5 carbon atoms; R<3> is Phe, D-Phe, Tyr, D-Tyr, Tyr(OMe), D-Tyr(OMe), Tyr(OEt), D-Tyr(OEt), Phe(4-Me), D-Phe(4-Me), Phe(4-Et) or D-Phe(4-Et); R<4> is Gln, Thr, Ser, Asn, or Val; and R<5> is Orn, Arg, Lys, Leu, or Ile; provided, however, that when X is hydrogen and R<3> is Tyr(OMe), R<4> may not be Thr or when X is hydrogen, R<3> is Phe and R<4> is Asn, R<5> may not be Orn. The polypeptides are oxytocin antagonists and are useful in inhibiting oxytocin induced contractions in mammals. |
