The kinetics of hypoxanthine efflux from the rat brain

Abstract

The brain efflux of radiolabelled hypoxanthine in the rat was rapid in the first minute after injection [Keff(i)=0.21±0.06 min-1], which was saturable with a Vmax=13.08±0.81 nM min-1 g-1, and a high Km.app (67.2±13.4 μM); the Ki.app for inosine was 31.5±7.6 μM. Capillary depletion analysis indicated that hypoxanthine accumulates in neurons and glia with the time. From cross-inhibition studies with different purines and pyrimidines, it suggests that these molecules could also be important substrates for this carrier. © 2001 Elsevier Science B.V.