Ontogenic changes in placental transthyretin

Abstract Objectives Before secretion of fetal thyroid hormone at around 16 weeks gestation normal fetal development depends on a constant supply of maternal thyroid hormone (TH), particularly thyroxine (T4 ). The detailed mechanisms of transplacental delivery of TH are still uncertain. The TH binding protein, transthyretin (TTR), is produced and secreted by placenta and may play a role in this process. The ontogeny of placental TTR is unknown. Our aim was to study changes in placental TTR in early and late pregnancy. Study design We collected placentas from surgically terminated pregnancies between 6 and 17 weeks gestation ( n = 44) and from normal term (38–39 weeks) pregnancies following caesarean section ( n = 5). Real time-PCR, western blotting and immunohistochemistry were used to determine TTR mRNA and protein levels. Results There were highly significant correlations between gestational age and TTR mRNA ( r = 0.974; p