Studies on I131-TSH (No.2)
TSH metobolism in the thyroid and peripheral tissues and the extraction of TSH from the blood and urine
1961 Volume 36 Issue 12 Pages 1996-2012,1941
Details
1961 Volume 36 Issue 12 Pages 1996-2012,1941
1) I131-TSH (inactivated) accumulated mainly in the liver and kidney, but did not accumulate in the thyroid gland, orbital tissue, thymus, lymphoid tissue, adrenal, ovary, uterus and muscle after I131-TSH injection in mice and rats.
2) P131-TSH was destroyed in the liver and kidney slices during the incubation.
3) I131-TSH did not accumulate in the rabbit's thyroid, but free I131 which was made from I131-TSH was uptaken by the thyroid gland in the lapse of the time.131The appearance rate of the free I131 made from P131-TSH in the blood and its uptake of thyroid were faster in the patient with hyperthyroidism than normal subject.
4) The half-time of the disappearence of I131-TSH in the blood was as follows : 131 in rabbits 1.5-2.0 h in normal subjects 2.5-3.5 h in hyperthyroidism 1.5 h
5) The half-time of the disappearence of I131-TSH was the same in normal as in thyroidectomized rabbit.
6) The. recovery percentage of TSH by Fellinger's method, which was examined by I131-TSH (Pretiron) as a indicator, was about 30%, and by Ueda's modification was 38%, and by the author's method (using the serum) was 55-60%.
By the author's modification, ACTH was extracted ea. 40% in this TSH fraction which was examined by I131-ACTH.
It was suspected that ACTH also contaminated in this TSH fraction by Fellinger's modification.
The recovery percentage of TSH which was extracted from the urine was about 50% by Cope's method.
7) TSH fraction obtained by Column chromatography (Amberlite IRC-50) was also very crude TSH and was contaminated with many substances, i.e. ACTH & Insulin.
8) It was suspected that the iodination reaction of TSH in vivo performed mainly in the thyroid cells.
9) From these results the following hypothesis is proposed, i.e. TSH which is secreted from hypophysis stimulate the thyroid cells, and acceralate the iodine metabolism in the gland. Then, TSH itself is inactivated.
The one type of the inactivation of TSH is “iodinated-TSH”. Thiouracil is the inhibitory action on the production of this “iodinated-TSH” by its reductive reaction, on the other hand maintains the activity of TSH.
The “iodinated-TSH” is not destroyed in the thyroid gland, but the “iodinated-TSH” is transported to the peripheral tissues and this is mainly destroyed in the liver and kidney.
