Figure 1.

Inhibition of receptor-stimulated cAMP accumulation by α_s mutants. COS-7 cells transfected with control plasmid pcDNAI or plasmids encoding wild-type or mutant HA-α_s (1.2 μg per 1.6 × 10⁶ cells per 60-mm dish) and the LH-R in PSG5 (0.2 μg per 1.6 × 10⁶ cells per 60-mm dish), were incubated at 37°C for 25 min with 100 μM IBMX and 75 ng/ml hCG (shaded bars) or no drug (hatched bars), and cAMP accumulation was measured. A and B represent results of two separate experiments, and all values represent means ± SD of triplicate determinations. Each set of results is representative of at least two additional experiments.