Journal of Endocrinology

Thyroid hormone and TH receptor concentrations in the human fetus. This figure contains replotted data on the concentrations of TH in coelomic and amniotic fluids (Burrow et al. 1994, Calvo et al. 2002) fetal serum (Thorpe-Beeston et al. 1991) and cerebral cortex (Kester et al. 2004) as a function of fetal age expressed in postmenstrual weeks. The lower part of the figure shows the number of T₃ receptor molecules per nucleus recalculated from the original publication (Bernal & Pekonen 1984) assuming 8 pg DNA/nucleus. The inset shows the relative affinity of the human fetal receptor for triac (T3A), T₃, T₄, rT₃ (Bernal & Pekonen 1984). The shaded bar marks the date at which the fetal thyroid gland concentrates iodine and contains thyroglobulin and iodinated compounds (Shepard 1967).