PROBLEM TO BE SOLVED: To provide a novel neurokinin 3 receptor (NK3 receptor) selective ligand useful as a therapeutic agent of a disease associated with the oversecretion or lack of tachykinins, such as an agent directed to the improvement of sexual dysfunction associated with pain, sex-hormone oversecretion and lack, the ligand being expected to highly actively and highly selectively act, as well as to continuously act in vivo.SOLUTION: Disclosed is a compound represented by formula (I) or a pharmaceutically acceptable salt thereof. Formula (I) X1-A2-A3-X4-X5-Met-NH2[ X1 represents a R1-A1 or a dicarboxylic acid residue which is modified directly or through a linker by one or two polyethyleneglycol (PEG) with a molecular weight 500-5,000, or a derivative thereof R1 represents an H or a particular chemical group A1 and A2 represent a particular D or L-amino-acid residue A3 represents a particular L amino acid which is N-methylated and X4 and X5 represent Gly-Leu or a dipeptide equivalent thereof.]SELECTED DRAWING: NoneCOPYRIGHT: (C)2017,JPO&INPIT【課題】タキキニン類の分泌の過剰もしくは欠乏に伴う疾患の治療薬、例えば、疼痛、性ホルモン分泌の過剰・欠乏にともなう性機能障害の改善に向けた薬剤等として有用な、高活性・高選択的かつ生体内で持続的に作用することが期待される新規ニューロキニン3受容体(NK3受容体)選択的リガンドの提供。【解決手段】式(I)でで示される化合物又はその医薬上許容される塩。式(I)X1-A2-A3-X4-X5-Met-NH2[X1は1又は2の分子量500~5,000のポリエチレングリコール(PEG)又はその誘導体で直接又はリンカーを介して修飾された、R1-A1或いはジカルボン酸残基を表し;R1はH又は特定の化学基;A1及びA2は特定のD又はLアミノ酸残基;A3はNメチル化された特定のLアミノ酸、X4及びX5は、Gly-Leu或いは、そのジペプチド等価体]【選択図】なし
