Premium
myo ‐Inositol Transport in Mouse Astroglia‐Rich Primary Cultures
Author(s) -
Wiesinger Heinrich
Publication year - 1991
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1991.tb02070.x
Subject(s) - inositol , phloretin , ouabain , cytochalasin b , sorbinil , sorbitol , biochemistry , chemistry , glucose uptake , amiloride , biology , in vitro , aldose reductase inhibitor , endocrinology , insulin , sodium , receptor , enzyme inhibitor , organic chemistry
Uptake of radiolabeled myo‐inositol was studied in astroglia‐rich primary cultures derived from neonatal mouse brains. The uptake was saturable in the presence of Na − with a K m of 25 μ M and a V max of 60 pmol·min − · (mg protein) −1 , suggesting a high‐affinity transport system for myo‐ inositol in astroglial cells. In addition, a Na + ‐independent, nonsaturable component was found. Camer‐mediated uptake was not inhibited by cytochalasin B (50 μ M ), but was reduced by depolarizing concentrations of K + and, to different extents, in the presence of phloretin, ouabain, or amiloride (1 mM each). scyllo‐Inositol, glucose, and galactose also reduced myo ‐inositol uptake; inhibition by the tmo hexoses was not reversed in the presence of 0.4 Wsorbinil. On the other hand, uptake of 2‐deoxyglucose was not inhibited by high concentrations of myo ‐inositol. Preincubation of the cells with glucose‐free or inositol‐free medium stimulated uptake of myo ‐inositol and preincubation with 25 mM glucose in the presence of 0.4 mM sorbinil had no effect on the rate of uptake. The results suggest that myo ‐inositol is taken up into the astroglial cells by a transport mechanism that is distinct from that of glucose and probably is an active one. Sorbitol pathway activity does not interfere with myo ‐inositol uptake.