| 摘要 |
<p>Polypeptides having formula (I), wherein X is hydrogen or -NH2; Y and Z are independently sulfur or CH2; R?1 and R2¿ are hydrogen, methyl, cyclopentamethylene or an alkyl group having 1 to 5 carbon atoms; R3 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); R4 is Gln, Thr, Ser, Asn, or Val; and R5 is Orn, Arg, Lys, Leu, or Ile; provided, however, that when X is hydrogen and R3 is Tyr(OMe), R4 may not be Thr or when X is hydrogen, R3 is Phe and R4 is Asn, R5 may not be Orn. The polypeptides are oxytocin antagonists and are useful in inhibiting oxytocin induced contractions in mammals.</p> |
