Endemic Goiter in Greece: Thyroid Hormone Kinetics

Publisher Website
Google Scholar
Abstract
The metabolism of labeled thyroxine (T4*) and triiodothyronine (T3*) was studied in patients with endemic goiter. The thyroidal recycling of labeled iodide was not blocked, but was calculated with the help of the computer model previously described. The peripheral metabolism of T4* was simulated by 3 compartments. The total space of distribution (11.2% of body weight) was smaller than previous estimates in other populations. There was no evidence that the low-normal PBI values previously reported in endemic goiter were compensated by an increased T4* turnover rate. On the contrary, the daily T4 metabolism (0.54 l/day or 32.4 μg/day) was rather low. T3* metabolism was simulated by 2 compartments, the first being approximately the sum of the 3 T4* compartments, the other corresponding to a larger space that is apparently not accessible to T4*. The metabolic clearance rate of T3* (19.5 l/day) was considerably greater than that of T4* (0.54 l/day). Taking into account published data on the T3 concentration in the serum, it may be concluded that in patients with endemic goiter T3 is probably of greater metabolic importance than T4, and probably accounts for the lack of clinical hypothyroidism in these patients despite the relatively low PBI levels.

This publication has 0 references indexed in Scilit: