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Abstract #4621

Two Site Water Exchange Analysis of Pancreatic T1 Relaxation Reveals the Kinetics and Mechanism of Beta Cell Labeling with Manganese: Implications for Imaging Beta Cell Mass in Diabetes

Patrick Antkowiak1, Moriel Vandsburger, Frederick Epstein

1University of Virginia, Charlottesville, VA, United States

The kinetics and mechanism of pancreatic β cell labeling with Mn2+ were investigated. Murine pancreatic T1 relaxation was measured in normals and after treatment with the Ca2+ channel blocker nifedipine. Two site water exchange analysis of pancreatic T1 relaxation provided the intracellular T1 and intracellular fraction, measures of β cell labeling. Increased intracellular T1 and lower intracellular fraction in nifedipine-treated mice confirmed Mn2+ enters β cells through Ca2+ channels. The timecourse of intracellular T1 and fraction in normal mice revealed 3 phases of Mn2+ kinetics: 1) labeling β cells, 2). washout from β cells, 3). nonspecific labeling of other cells.