Patent ID: 7232559

Claim:
A 13 C- or 14 C-labeled compound used for measuring pancreatic exocrine function, said compound represented by the following formula (II): X 2 —R 2 —Y 2 —Z 1 (II) or salt thereof, wherein X 2 is a benzoyl group, R 2 is a peptide of 2 to 5 amino acids, an amino acid or a single bond, Y 2 is an amino acid, Z 1 is an amino acid optionally having a protecting group, and at least one of the amino acids in R 2 , Y 2 , and Z 1 , or at least one of the protecting groups in X 2 and Z 1 when the protection groups contain a carbon atom, is 13 C- or 14 C-labeled, wherein in the case where R 2 is a single bond, Z 1 is D-Ala and Y 2 is an amino acid other than D-Ala, Z 1 is L-Ala-OMe and Y 2 is an amino acid other than L-Leu, or Z 1 is L-Pro-OMe and Y 2 is an amino acid other than L-Gly; in the case where R 2 is an amino acid, Z 1 is D-Ala and Y 2 is an amino acid other than L-Val, Z 1 is L-Ala and Y 2 is an amino acid other than L-Leu, or Z 1 is L-Gly-OEt and Y 2 is an amino acid other than L-Pro, or in the case where R 2 is a peptide of 2 amino acids, Z 1 is L-Gln optionally having SEt, and Y 2 is an amino acid other than L-Ala.