Fig. 6. The uptake of [125I]-RAP by brain parenchyma was greater than that in the capillaries and that of [99mTc]-albumin, and was inhibited by excess RAP. This indicates the presence of a saturable transport system. *Significant difference (P<0.05) in reactivity ratio between parenchymal [125I]-RAP and inhibited [125I]-RAP groups.