Table 1.
The number of animals used in each experiment.
Fig 1.
Standard curves for radioimmunoassay (RIA) and serum thyroid hormone levels in zebra finches.
Typical standard curves for (A) T4 and (B) T3 are shown. Each point represents the average of duplicate measurements. Standard deviations were small and fell within the symbols. (C) Comparison of T3 and T4 in serum for males and females averaged through time post-hatching (gray ○, T4; gray □, T3). A two-way repeated measures ANOVA was done following Bartlett’s test for homogeneity of variance. The significance level was set at P < 0.05. Mean ± SEM are reported in the graphs.
Fig 2.
Serum thyroid hormone levels in male and female zebra finches.
Comparisons between male and female zebra finches for (A) total concentrations of T3 and T4 (▲, T3 + T4 male;△, T3 + T4 female), (B) T4 (●, male T4; ○, female T4.), and (C) T3 (■, male T3; □, female T3) levels through days post-hatching. A two-way factorial ANOVA was done following Bartlett’s test for homogeneity of variance. The significance level was set at P < 0.05. Mean ± SEM are reported in the graphs.
Fig 3.
Brain thyroid hormone levels in male and female zebra finches.
Comparisons of male and female brain thyroid hormones through time after hatching for (A) total concentrations of T3 and T4 (▲, T3 + T4 male; △, T3 + T4 female), (B) T4 (●, male T4; ○, female T4.), and (C) T3 (■, male T3; □, female T3). Kruskal-Wallis tests were used to analyze the concentration of thyroid hormones in brains. Mann-Whitney’s U-test with Bonferroni correction was used for post-hoc multiple comparisons. The significance level was set at P < 0.05. Mean ± SEM are reported in the graphs.
Fig 4.
Dio2 mRNA levels in male zebra finches.
Comparison of Dio2 mRNA levels in male zebra finches at 21 (n = 4), 33 (n = 4), and 44 dph (n = 4). The Kruskal-Wallis test and subsequent multiple comparisons were performed. The significance level was set at P < 0.05. Mean was shown in the graphs as a bar.
Fig 5.
Thyroid hormone receptor in the male zebra finch brain.
(A, B) Zebra finch male brain sections (A; dph 22, B; dph 44) were used for immunostaining. Labeling of thyroid hormone receptor (TR) alpha protein (left) and NeuN, a neuron specific marker protein (middle) in the same male zebra finch brain section. Images shown in the left and middle have been combined (right). Arrows show brain cells that were not labeled with NeuN. Bars in A and B indicate 25 μm. (C) Male zebra finch brain section (dph 44) was labeled by TR (left) and NeuN (right). (D) Schematic drawing of the section shown in C. Bars in C and D indicate 2.5 mm.