Assessment of Myocardial Metabolism in Diabetic Rats Using Small-Animal PET: A Feasibility Study

This feasibility study was undertaken to determine whether kinetic modeling in conjunction with small-animal PET could noninvasively quantify alterations in myocardial perfusion and substrate metabolism in rats. Methods: All small-animal PET was performed on either of 2 tomographs. Myocardial blood flow and substrate metabolismweremeasured in 10male Zucker diabetic fatty rats (ZDF, fa/fa) and 10 lean littermates (Lean, Fa/1) using 15O-water, 1-11C-glucose, 1-11C-acetate, and 1-11C-palmitate. Animals were 12.06 1.4-wk old. Results: Consistent with a type 2 diabetic phenotype, the ZDF animals showed higher plasma hemoglobin A1c, insulin, glucose, and free fatty acid (FFA) levels than their lean controls. Myocardial glucose uptake (mL/g/ min) was not significantly different between the 2 groups. How-ever, higher glucose plasma levels in the ZDF rats resulted in higher myocardial glucose utilization (nmol/g/min) (Lean, 629 6 785, vs. ZDF, 1,737 6 1,406; P 5 0.06). Similarly, myocardial FFA uptake (mL/g/min) was not significantly different betwee