. Author manuscript; available in PMC: 2019 Sep 5.

Published in final edited form as: Toxicol Sci. 2018 Nov 1;166(1):163–179. doi: 10.1093/toxsci/kfy190

Table 3. Mathematical relationship describing thyroid hormone dynamics in the GD20 fetus and PN14 pup.

Equations resulting from analyses of serum and brain THs at both stages. Equations were derived from mean or percent change T4 and T3 as indicated. In all equations x 1/4 quantified serum or brain T4. The top equations are for use with mean values, and the bottom percent control. In the percent control equations, solve for y given negative x values (to represent TH detriment).

Means	Serum T4 vs. brain T4	Serum T4 vs. brain T3	Brain T4 vs. brain T3
GD20 fetus	y = 0.183x + 0.023	y = 0.780 (1 − e^−6.97x)	y = 0.955x + 0.141
PN14 neonate	y = 0.0015x² − 0.018x + 0.090	y = 0.126 (1 − e^−4.87x)	y = 7.328 (1 − e^−3.52x)
Percent change	Serum T4 vs. brain T4	Serum T4 vs. brain T3	Brain T4 vs. brain T3
GD20 fetus	y = 0.013x² + 2.219x − 0.395	y = 7.000 (1 − e^−0.028x)	y = 0.003 (1 − e^−0.103x)
PN14 neonate	y = 1.031x + 7.030	y = 8.236 (1 − e^−0.026x)	y = 0.828x + 3.582