A radiopharmaceutical for pancreatic exocrine functional diagnosis: 62Zn-EDDA metabolism in pancreas

The metabolic pathway of radioactive ⁶²Zn-EDDA (ethylenediamine-N,N′-diacetic acid), in the exocrine pancreas was studied with respect to that of endogenous Zn. In pancreatic duct cannulated dog, the secretion of intravenously injected exogenous ⁶²Zn into pancreatic juice increased under the stimulation of CCK-PZ (pancreatic protein secretion stimulating hormone), which closely correlated to endogenous Zn. Moreover, in pancreatic juice, ⁶²Zn as well as endogenous Zn was selectively bound to Zn-metalloenzymes, carboxypeptidase A and B. These results demonstrated the close correlation between the endogenous and the exogenously-administered Zn (⁶²Zn-EDDA), as well as the high availability of ⁶²Zn-EDDA as a marker of pancreatic function for the follow up of carboxypeptidase metabolism.