Regulation by insulin and insulin-like growth factor of 2-deoxyglucose uptake in primary ependymal cell cultures.
Ependymal cells have been reported to express the facilitative glucose carriers GLUT1, GLUT2, and GLUT4, as well as glucokinase. They are therefore speculated to be part of the cerebral glucose sensing system and may also respond to insulin with alterations in their glucose uptake rate. A cell culture model was employed to study the functional status of ependymal insulin-regulated glucose uptake in vitro. Insulin increased the uptake of the model substrate 2-deoxyglucose (2-DG) dependent on the insulin concentration. This was due to a near doubling of the maximal 2-DG uptake rate. Insulin-like growth factor (IGF-1) was at least 10 times more potent than insulin in stimulating the rate of ependymal 2-DG uptake, suggesting that IGF-1, rather than insulin, is the physiological agonist regulating glucose transport in ependymal cells. The predominant glucose transporter in ependymal cell cultures was found to be GLUT1, which is apparently regulated by IGF-1 in ependymal cells.
Physiologisch-Chemisches Institut der Universität, Hoppe-Seyler-Str. 4, D-72076 Tübingen, Germany. Stephan.Verleysdonk@uni-tuebingen.de
Stephan
S
Verleysdonk
Wolfgang
W
Hirschner
John
J
Wellard
Mirna
M
Rapp
Maria
M
de los Angeles Garcia
Francisco
F
Nualart
Bernd
B
Hamprecht
D001483:Base Sequence; D017931:DNA Primers; D003847:Deoxyglucose / Q000378:metabolism*; D004805:Ependyma / Q000166:cytology / Q000378:metabolism*; D007328:Insulin / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D007328:Insulin; D007334:Insulin-Like Growth Factor I; D003847:Deoxyglucose