Using video intensification fluorescence microscopy and tetramethylrhodamine (Rho)-labeled 3, 3', 5-triiodo-L-thyronine (T3),the uptake of T3 by cultured mouse fibroblasts was studied. The binding of 3, 3', 5-triiodo-L-thyronine (T3) to GH3 rat pituitary tumor cells was studied at 15 degrees C and was shown to be saturable, reversible, and stereospecific. A fluorescent derivative of the thyroid hormone 3,3'-triiodo-L-thyronine binds to cultured mouse fibroblasts; such binding is saturable. 3,3?,5-Triiodo-L-thyronine Up-regulation of Na,K-ATPase Activity and Cell Surface Expression in Alveolar Epithelial Cells Is Src Kinase- and Phosphoinositide 3-Kinase-dependent.
