TAGGED ISOMERS AND ANALOGUES OF THYROXINE (THEIR TRANSMISSION ACROSS THE HUMAN PLACENTA AND OTHER STUDIES).

Results are reported from studies of the transmission of thyroxine, its analogs and isomers, through the placental membrane using I/sup 131/ as a tracer. Some physiological properties of tagged isomers and analogs of thyroxine are reported. It was concluded that they are decreased in cord blood although there is complete transmission of NaI/sup 131/. There seems to be a specific distributional difference between thyroxine and triiodothyronine in its collections in body areas. Excretion in bile and rapid re-absorption in the gut were shown. (auth)