Thyroxine utilization rate in sucking pigs

In 10 suckling pigs age 28--34 days, thyroxine utilization rate (TUR) was determined by means of the isotope dilution procedure. For this purpose biological half-life of T4 was estimated during 96 h of blood sampling and serum T4 concentration was measured directly by a competitive protein-binding technique. High rate of the peripheral hormonal-iodine metabolism (from 10.3 +/- 0.6 to 21.2 +/- 1.2 mug T4/kg/day) was found in the one-month old pigs. TUR value calculated for these pigs corresponds to that reported in human infants and it is much higher than in the growing ruminants.