Figure 2.

Compound 52 (c52) inhibits TSHR activation by TSH and TsAbs of Graves’ disease sera. A, Intracellular cAMP accumulation in HEK-EM 293 cells stably expressing TSHR was determined in response to a 1:50 dilution of sera from patients with Graves’ disease (GD) or the EC₅₀ concentration of bovine TSH (1.8 nm) in the presence or absence of c52. Serum from a patient with multinodular goiter was used as a control. The data are presented as mean ± sem of four independent experiments. B, c52 inhibits TPO mRNA expression in primary cultures of human thyrocytes from donor 2 stimulated by bovine TSH or GD sera. Thyrocytes were incubated with bovine TSH (1.8 nm) or a 1:50 dilution of GD sera and 10 μm of c52 for 24 h. Cells receiving 10 μm c52 were preincubated for 1 h with the same concentration of c52 before the 24-h incubation with bovine TSH. Data are presented as mean ± sem of two independent experiments.