Fig. 2
From: QimmeqHealth—thyroid status of Greenland sled dogs (Canis lupus familiaris borealis)
Correlation between age and T4, fT4, and TSH concentrations in healthy Greenland sled dogs. Lines represent linear correlation between age and thyroid hormones. Shaded areas denote 95% confidence intervals. A positive significant correlation with slope of 0.014 ng/mL/year is shown between age and TSH. No significant correlation was present between age and T4 and fT4. a T4, b fT4, c TSH