Figure 3.

Compensated primary hypothyroidism and mRNA expression of thyroid hormone synthesis machinery in Ctns^−/− mice. A, Ctns^−/− mice elicit a compensatory TSH increase. T₄, T₃, and TSH plasma concentrations were measured in 9- to 10-month WT mice (open symbols) and Ctns^−/− littermates (filled symbols) (n = 18 for T₄; n = 9 = WT and 8 Ctns^−/− for T₃; n = 20 for TSH). Ctns^−/− mice show an average 4-fold increase in plasma TSH level but still normal thyroid hormone plasma levels, indicating effective thyroid compensation. B, Expression of thyroid-specific genes involved in hormone synthesis. Quantification by RT-qPCR of TSH receptor (TSHR), Na/I symporter (NIS), pendrin (PDN), DUOX2, DUOXA2, thyroperoxidase (TPO), DEHAL1 and MCT8 mRNAs in WT and Ctns^−/− thyroids collected at 9 and 12 months, normalized to actin mRNA (ACT) and presented as ΔCt values (difference of cycle threshold).