Exogenously administered
fructose-1,6-diphosphate (
FDP) has been studied for its ability to protect tissue during
hypoxia or
ischemia. Recently, a clear effect of
FDP on the central nervous system has raised the question whether
FDP can get into the brain.
FDP levels were measured in blood, brain, liver, kidney, muscle and fat after intraperitoneal administration of a single 0.5gkg(-1) dose of
FDP to adult male Sprague-Dawley rats. A complete time course of the levels in blood and brain was determined. The levels of
FDP in the blood and brain increase simultaneously, i.e. there is no lag in the increase in the brain. The levels of
FDP fall to baseline in liver, kidney, muscle and fat by 12h, but remain elevated in blood and brain. However, levels in the blood at 12h are significantly decreased from the peak levels, while those in brain are not different from the peak levels, suggesting that the kinetics of
FDP in blood and brain are quite different. Stripping the endothelial cells from the brain tissue sample did not change the levels of
FDP indicating that
FDP is not trapped in the capillary cells. Incubation of brain slices in a
solution of
FDP, followed by washing, raised tissue levels of
FDP indicating that
FDP is taken up into cells within the brain. Finally, the experiments demonstrate a significant increase in brain levels of
FDP after
oral administration. These data suggest that an oral formulation of
FDP might be developed for treatment of neurological disease.