Neuromedin U derivative

A compound represented by formula

• wherein Y represents a polypeptide consisting of an amino acid sequence set forth in SEQ ID NO.:
• 1 wherein 1 to 4 amino acids are substituted,
• the amino acid substitution is selected from:
• (1) substitution of Tyr at position 1 with Arg, NMeArg, or Pro;
• (2) substitution of Phe at position 2 with Nal(2);
• (3) substitution of Leu at position 3 with Gln, Arg, Val, Cha or NMeArg;
• (4) substitution of Arg at position 5 with Gln or NMeArg;
• (5) substitution of Pro at position 6 with NMeAla;
• and
• (6) substitution of Arg at position 7 with Arg(Me);
• X represents a methoxypolyethylene glycol;
• X′ is absent or represents a methoxypolyethylene glycol;
• La is a divalent or trivalent group represented by formula
• wherein R represents a bond and n is an integer of 0;
• Lb represents —(CH2)i— wherein I is an integer of 1 to 5;
• Lc is a divalent group represented by formula (i):
• —NH-Qc-Cb—
• wherein Qc is a divalent group represented by formula:
• —(CH2)m1—
• wherein m1 is an integer of 0 to 15, and Cb represents a bond, —CO— or —SO2—, or
• a divalent group represented by formula (ii):
• -Qc′-Cb′—
• wherein Qc represents a divalent group selected from formula:
• —(CH2)m1′—Zc′—(CH2)m2′—
• wherein m1′ is an integer of 0 to 15,
• Zc′ represents
• and m2′ is an integer of 0 to 15, and
• Cb represents a bond, —CO— or —SO2—;
• and
• j is an integer of 1 to 3;
• or
• a salt thereof,
• wherein the amino acid substitution includes (1) substitution of Phe at position 2 with Nal(2);
• (2) substitution of Pro at position 6 with NMeAla;
• or both.