Fig. 1. Formation of a charge-reinforced H-bond between positions 3.43 and 6.44 causes constitutive activation of the hLHR.

HEK293 cells were transiently transfected with increasing concentrations of cDNAs encoding the indicated hLHR constructs. In the same experiment, cell surface receptors (reflected by hCG binding assays to intact cells) and basal cAMP levels were determined as described under “Materials and Methods.” One experiment, representative of at least three is shown. Data show the mean ± S.E. of triplicate determinations within the experiment.