1Instituto de Investigaciones
Biomdicas "Alberto Sols" - CSIC, Madrid, Spain; 2Laboratory
of Organic Synthesis and Molecular Imaging, UNED, Madrid, Spain
We
investigate the mechanism of reduction of commercially available misonizazol
or pimonidazol and the newly synthesized NIMAC hypoxia probe. We followed by
in vitro 1H NMR the P-450 reductase dependent reduction of
solutions containing NADPH and the different hypoxia probes in the presence
or not of reduced glutathione, either under the air oxygen tension or under
anoxic conditions. We found that the oxygen content of the solution had only
a small effect of the different reduction rates, the rate limiting step being
in all cases the presence or not of reduced glutathione, independently of the
oxygen tension achieved.