Heterocyclic compound

1. A compound represented by the following formula:

wherein ring AA is an optionally substituted benzene ring;

ring AB is an optionally substituted furan ring;

ring AC is an optionally substituted benzene ring;

R A3 is a C 1-6 alkyl group or a C 3-10 cycloalkyl group;

R A4 is a hydrogen atom or a C 1-6 alkyl group;

R A5 is NR A6 —CR A7 R A8 —CR A9 R A10 —COOR A11 ;

R A6 , R A7 , R A8 , R A9 and R A11 are each independently a hydrogen atom or a C 1-6 alkyl group; and

R A10 is a hydrogen atom, a C 1-6 alkyl group or a hydroxy group,

or a salt thereof.

2. The compound of claim 1 , wherein

R A4 is a hydrogen atom;

R A5 is NR A6 —(CH 2 ) 2 —COOR A11 ;

R A6 is a hydrogen atom or methyl; and

R A11 is a hydrogen atom, methyl or ethyl.

3. 3-{[(4-{[Cyclohexyl(3-methyl-1-benzofuran-2-yl)methyl]amino}phenyl)carbonyl](methyl)amino}propanoic acid or a salt thereof.

4. 3-{[(4-{[2-Ethyl-1-(5-fluoro-3-methyl-1-benzofuran-2-yl)butyl]amino}phenyl)carbonyl](methyl)amino}propanoic acid or a salt thereof.

5. 3-[{[4-({1-[5-(Cyclopropylmethoxy)-3-methyl-1-benzofuran-2-yl]-2-methylpropyl}amino)phenyl]carbonyl}(methyl)amino]propanoic acid or a salt thereof.

6. 3-[{[4-({Cyclohexyl[3-methyl-5-(tetrahydro-2H-pyran-4-yloxy)-1-benzofuran-2-yl]methyl}amino)phenyl]carbonyl}(methyl)amino]propanoic acid or a salt thereof.

7. A pharmaceutical composition comprising the compound of claim 1 or a salt thereof, and a pharmacologically acceptable carrier.

8. A method of suppressing sugar production in a mammal, comprising administering the compound of claim 1 or a salt thereof to the mammal.

9. A method for the prophylaxis or treatment of diabetes in a mammal, comprising administering the compound of claim 1 or a salt thereof to the mammal.

10. 3-{[(4-{[Cyclopentyl(5-fluoro-3-methyl-1-benzofuran-2-yl)methyl]amino}phenyl)carbonyl](methyl)amino}propanoic acid or a salt thereof.