TmDOTP5- as a Na-23 shift reagent for the subcutaneously implanted 9L gliosarcoma in rats

The use of TmDOTP5- as an in vivo Na-23 NMR shift reagent (SR) for subcutan eously implanted 9L gliosarcoma was evaluated. TmDOTP5- produced a single s harp extracellular peak after about 50-60 min of infusion, and did not caus e any changes in the P-31 resonance areas or chemical shifts, suggesting th at the SR is homogeneously distributed in the extracellular space and does not alter tumor bioenergetic status. TmDOTP5- and CoEDTA(-) as extracellula r space markers gave identical results for relative extracellular space (0. 25 +/- 0.03 and 0.25 +/- 0.04, respectively) and intracellular Na+ concentr ation (19.3 +/- 4.0 mM and 18.6 +/- 3.9 mM, respectively), indicating that the biodistribution of the SR is the same as the well-accepted extracellula r space marker. The in vivo T-1 and T-2 relaxation times of intra- and extr acellular Na+ were also measured. Our results indicate that TmDOTP5- promis es to be an effective shift reagent and extracellular space marker in the 9 L gliosarcoma and perhaps other tumors. (C) 2001 Wiley-Liss, Inc.