Neonatal Fischer 344 rats were immunosuppressed with antithymocyte serum and later were given an injection intracerebrally of cells from the human
glioma permanent line D-54MG. Symptomatic
tumor-bearing rats were studied with double-label quantitative autoradiography to concurrently measure blood flow and a unidirectional blood-to-tissue transfer constant (K) for
alpha-aminoisobutyric acid (AIB). A net extraction fraction (En) was calculated from the measured values for blood flow and K. Mean whole
tumor blood flow was 53.5 +/- 4.9 ml/100 g/min (mean +/- SEM), which was significantly less than the blood flow to the
tumor-free cortex (198 +/- 15.5 ml/100 g/min) but not significantly different from the blood flow in the
tumor-free corpus callosum (50.6 +/- 4.3 ml/100 g/min). Mean whole
tumor K-value for AIB was 5.8 +/- 0.5 ml/100 g/min, approximately 30 times the K-value for
tumor-free brain. The calculated mean whole
tumor En was 0.2 +/- 0.09, nearly 100 times the value for the
tumor-free brain. Regionally, blood flow was lower in the
tumor center and higher in its
tumor periphery, although the difference was not significant. Both K- and En-values were significantly higher for the
tumor center and decreased radially for the areas from center out. The values for K and En of AIB in the D-54MG
gliomas are the highest of any experimental
brain tumor model studied to date and indicate that in some
tumor regions in this model, blood-to-tissue transport of the water-soluble compound AIB may be dependent on blood flow as well as on the permeability-surface area product of the
tumor capillaries.