Figure 2.

TSH stimulation of intracellular cAMP in CHO cells expressing TSHR mutants within the N-terminal portion of the hinge region (amino acid residues 261–289). After transient transfection, aliquots of the same cells used in the experiment shown in Fig. 1C were transferred to 96-well plates and stimulated with the indicated concentrations of bTSH (Materials and Methods). The effective dose of TSH required for half-maximal stimulation of intracellular cAMP levels (EC₅₀) is indicated by the arrows. Each point represents the mean plus range of determinations in duplicate wells. This experiment was repeated twice with similar results.