title: The influx of isoleucine into the cerebral hemispheres and cerebellum: carrier-mediated transport and diffusion.
abstract: The influx of L-isoleucine from the blood into the cerebral hemispheres, and into the cerebellum, of the living rat was studied. When various raised levels of L-isoleucine were maintained in the circulation, influx did not increase in proportion to the raised blood levels, which showed that a carrier-mediated transport was being saturated. It was found that the values for influx could not be explained precisely by Michaelis-Menten kinetics. The divergence of the observed values for influx, from those which were obtained by the application of Michaelis-Menten kinetics, could be explained if part of the influx was due to a small, non-saturable component. This minor component of influx may be due to diffusion or to a second carrier-mediated transport system that is not readily saturated.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D001812:Blood-Brain Barrier; D001921:Brain / Q000378:metabolism*; D002531:Cerebellum / Q000378:metabolism; D004058:Diffusion; D007532:Isoleucine / Q000097:blood / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D051381:Rats
chemical_list: D007532:Isoleucine