Figure 1.

Thyroid State of Skeletal Muscle in TH Transporter-Deficient Mice

(A) Measuring serum TH concentrations in 4-month-old female mice (n = 8) revealed highly elevated serum T3 and decreased serum T4 values in Mct8 deficiency, thereby replicating the characteristic TH serum profile of male Mct8 KO animals.

(B) TA muscle T3 content was almost 4-fold elevated in Mct8 KO and M/O DKO mice, while muscle T4 levels were reduced in M/O DKO mice only (n = 4 Mct8 KO; n = 5 WT, Oatp1c1 KO, M/O DKO mice).

(C) D2 and D3 enzymatic activities were measured in TA muscle homogenates. M/O DKO mice showed a pronounced rise in D2 and D3 activities (n = 6).

(D) qPCR analyses were performed using TA muscle homogenates from 2- to 3-month-old female mice to assess transcript levels of TH-regulated genes.

Group means + SEM are shown. n = 3 Mct8 KO; M/O DKO; n = 5 WT, Oatp1c1 KO mice.

^∗p < 0.05; ^∗∗p < 0.01; ^∗∗∗p < 0.001. Two-way ANOVA and Bonferroni-Holm post hoc testing.