Glucose transport in astrocytes: regulation by thyroid hormone.
Primary cultures of astrocytes from newborn rat brain showed evidence of a substrate-saturable process for glucose transport. The system shows a relatively high affinity for the substrate, with an apparent Km of approximately 1 mM. Maintenance of the cells in medium containing thyroid-hormone-free serum for 3, 6, or 9 days resulted in significantly reduced rates of hexose transport. Addition of exogenous triiodothyronine to the transport incubation medium of these "hypothyroid" cells markedly increased the net rate of 2-deoxyglucose uptake within 60 s to values equal to or above those of control cultures (cells maintained in normal serum). These findings support a key role for thyroid hormone in the transport of glucose across plasma membranes of brain cells and demonstrate the presence of this regulatory system in astrocytes.
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D001693:Biological Transport, Active / Q000187:drug effects; D001921:Brain / Q000378:metabolism*; D003994:Bucladesine / Q000494:pharmacology; D002478:Cells, Cultured; D003470:Culture Media; D003837:Deoxy Sugars / Q000378:metabolism*; D003847:Deoxyglucose / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D014284:Triiodothyronine / Q000494:pharmacology*
D003470:Culture Media; D003837:Deoxy Sugars; D014284:Triiodothyronine; D003994:Bucladesine; D003847:Deoxyglucose