Transport of Hexoses and Monocarboxylic Acids

Although the dependence of the mammalian brain, under normal conditions, on a regular supply of glucose from the bloodstream has been acknowledged for 50 years or more, ways by which glucose passes to the brain and how it travels within the brain were ignored until relatively recently. Even though efforts were devoted to movement of glucose to the brain overall in the middle 1960s, any curiosity about transport of the sugar through the constituent cellular compartments began to emerge only within the last decade. Thus, in reviews of 20 years ago,1,2 the tacit assumption was that the glucose got into the brain by passive diffusion: there seems to have been no reported research that gave evidence of any carrier-mediated mechanism, though the possibility had been suggested.3