Development of the independent function of fetal thyroid glands in the dog in connection with iodothyronine concentrations in pregnant bitches, fetal fluids, and fetal serum
Pregnant and non-pregnant T4 levels exceeded the normal healthy range. Fetal serum T4 concentrations were lower than the concentrations of the adults. Fetal T4 concentration continuously increased until the birth. Fetal serum T4 were lower than concentrations of the allantois and amnion. Maximal T3 of the fetal fluids exceeded the fetal, maternal serum concentrations. The function of fetal thyroid gland is independent from the maternal thyroid gland.