A manganese(II)-Based Responsive Contrast Agent Detects Glucose- Stimulated Zinc Secretion from the Mouse Pancreas and Prostate by MRI.

A Mn(II)-based zinc-sensitive MRI contrast agent, Mn(PyC3A)-BPEN, was prepared and characterized and the agent was used in imaging experiments to detect glucose-stimulated zinc secretion (GSZS) from the mouse pancreas and prostate in vivo. Thermodynamic and kinetic stability tests showed that Mn(PyC3A-BPEN) has superior kinetic inertness compared to Gd(DTPA), is less susceptible to transmetallation in the presence of excess Zn²⁺ ions, and less susceptible to transchelation by albumin. In comparison with other gadolinium-based zinc sensors bearing a single zinc binding moiety, Mn(PyC3A-BPEN) appears to be a reliable alternative for imaging b-cell function in the pancreas and glucose-stimulated zinc secretion from prostate cells.