Figure 5.

Inhibition of basal cAMP production and of the basal expression of mRNAs for TPO, TSHR, TG, NIS, and DIO2 by 1 in primary cultures of human thyrocytes. A, Thyrocytes were incubated in HBSS without or with 1 mm IBMX and without (control) or with increasing concentrations of 1 for 2 h at 37 C. Thereafter, the buffers were aspirated, the cells were lysed, and intracellular cAMP was measured by ELISA. The basal activity without IBMX was subtracted from all samples. B, Thyrocytes were incubated in DMEM containing 2% FBS and 1 mm IBMX without or with 30 μm 1 as described in Materials and Methods. After 48 h, the cells were lysed and the levels of the mRNAs were measured and normalized to GAPDH mRNA. The mRNA levels are presented as percentage of basal activity (control). The data from two independent experiments with duplicate samples are shown.