Table 1.

Hormones and regulatory peptides as substrates for DPP-4 (modified according to Mentlein (1999)

With influence on activity and elimination	Without influence on activity and elimination
GLP-1	GRH
GIP	Interleukin 1β
GLP-2	Interleukin 2
PACAP	IGF-1
NPY	Prolactin
PYY	HCG
Substance	Bradykinin
RANTES

Abbreviations: DPP-4, dipeptidyl-peptidase inhibitor; GIP, gastric inhibitory polypeptide; GLP, glucagon-like peptide; GRH, gonadotrophin-releasing hormone; HCG, human chorionic gonatotrophin; IFG-1, insulin-like growth factor-1; NPY, neuropeptide Y; PACAP, pituitary adenylate cyclase-activating polypeptide; PYY, peptide YY; RANTES, regulated on activation, normal T cell expressed and secreted.