Concentration of thyroglobulin, iodine contents of thyroglobulin and of iodoaminoacids in human neonates thyroid glands.

The iodine and protein concentrations, the iodoamino acids content of thyroglobulin (TG) were determined in 17 thyroid tissues from human neonates who died from 3 hours to 47 days after birth. Total iodine concentration of neonate tissues increased with life duration. TG concentration was related to the survival duration of the neonates. Increase of the iodine content was associated to the increase of the TG content: mean value was 0.16 mug 127I/100 mug TG in neonates who died within the first 20 hours after birth, 0.25 mug in neonates who survived 26 to 72 hours and 0.43 mug in neonates living more than 10 days. Expressed as iodine content to total iodine ratio, iodoamino acid percentages were not related to the tissue. When the iodoamino acids were expressed in residues per molecule of TG, iodtyrosines, thyroxine and triiodothyronine increased with duration of survival. These variations in iodine content and concentration of thyroglobulin could be related to acute hormonal changes in serum observed in early neonatal period.