Comparison of organ uptake (%ID/g) of DMP444 and P4-DMP444 in the blood (A), heart (B), Lung (C) and muscle (D) of Sprague-Dawley rats (n = 4) at 5, 30, 60 and 120 min p.i. At 5 min p.i., P4-DMP444 had significantly lower (p < 0.05) uptake than DMP444; but this difference disappeared at later times (>15 min p.i.).