Thyrotropin Stimulates Glucose Transport in Cultured Rat Thyroid Cells

摘要: Glucose transport by FRTL-5 cells, a rat thyroid cell line, was found to be TSH dependent. The effect of on the uptake 2-deoxy-D-glucose, nonmetabolizable glucose analogue, prompt, being 200% over basal value after 10 min and maximal 12 h (600-700% increase). dose dependent, with half-maximum stimulation at microU TSH/ml, maximum 1 mU TSH/ml. enhanced also 3-O-methyl-D-glucose cells. activation had following characteristics: it mimicked (Bu)2-cAMP (1 mM) agents that increase cAMP levels in such as forskolin (10 microM) cholera toxin (50 micrograms/ml); involved facilitated system inhibited dose-related manner both cytochalasin B phloretin; showed stereochemical sensitivity, affected D-glucose 3-O-methyl-glucose, not L-glucose; characterized an velocity (Vmax) (from 15.3 66.0 fmol/min X micrograms DNA) without change Michaelis-Menten constant (Km) (5.3 mM); Vmax due number surface transporters indicated enhancement D-glucose-sensitive fraction [3H]cytochalasin binding sites plasma membranes cells exposed for 2 8 h, increased from 5.0 (basal value) 10.4 23.1 pmol/mg protein, respectively. These data indicate stimulates functional membrane.