Figure 3

Phenotypes of Slc26a7^−/− and Slc26a4^−/− mice on a low iodine diet. (a) Urine iodine levels of female Slc26a7^+/− mice with normal and low iodine diets; n = 6 mice in each group. **p < 0.01 determined by Student’s t test. (b) Growth curve of male wild type (WT), Slc26a7^+/−, Slc26a7^−/−, and Slc26a7^−/− mice receiving l-thyroxine (L-T4) replacement from day 21 with a low iodine diet. Note that Slc26a7^−/− mice without thyroid hormone replacement did not survive. (c) Serum free thyroxine (FT4) levels in male WT, Slc26a7^+/−, and Slc26a7^−/− mice with normal and low iodine diet at day 21; n = 4–5 mice of each genotype. Two-way analysis of variance (ANOVA) showed significant effects of genotype (F (2, 20) = 29.92, p < 0.0001). **p < 0.01, ***p < 0.001 determined by Tukey’s test compared with WT mice with same diet. (d) Serum FT4 levels in male WT, Slc26a4^+/−, and Slc26a4^−/− mice that were fed a low iodine diet, at day 90; n = 4–5 mice of each genotype. One-way ANOVA showed no significant differences among the three groups (F (2, 10) = 0.19, p = 0.83). WT wild type, L-T4 l-thyroxine, FT4 free thyroxine.