Radioimmunoassay for 3,3',5'-L-triiodothyronine (reverse T/sub 3/): assessment of thyroid gland content and serum measurements in conditions of normal and altered thyroidal economy and following administration of thyrotropin releasing hormone (TRH) and thyrotropin (TSH). [/sup 125/I tracer technique]
The present report describes the development of a radioimmunoassay for 3,3',5'-L-triiodothyronine (reverse T/sub 3/) which is performed on unextracted serum. Utilizing this radioimmunoassay, 21 normal subjects had a mean (+-SD) serum reverse T/sub 3/ level of 60 +- 12 ng/100 ml, 17 of 19 hyperthyroid patients had elevated serum reverse T/sub 3/ levels, and 10 of 11 hypothyroid subjects had decreased serum reverse T/sub 3/ concentrations. Thyroidal secretion of reverse T/sub 3/ was assessed by measurements in samples obtained from the internal carotid artery and jugular vein of sheep following the administration of thyrotropin releasing hormone (TRH) or bovine thyrotropin (TSH). Reverse T/sub 3/ levels were increased 45-60 min after TRH administration, but TSH administration produced inconsistent alterations in reverse T/sub 3/, although 18 of 27 samples obtained after TSH injection were higher than their average respective baseline concentration and the mean peak reverse T/sub 3/ level was 14 percent higher than baseline. Following TRH administration to 10 normal human subjects, mean serum reverse T/sub 3/ levels significantly increased from 53.6 ng/100 ml to 56.3 ng/100 ml (P less than .05). The thyroid gland content of reverse T/sub 3/ in human autopsy material was 6.5 +- 1.5 ..mu..g/g tissue. Both pregnancy and estrogen administration were associated with increases in serum reverse T/sub 3/ concentrations presumably because of their ability to augment thyroxine binding globulin synthesis.
- Research Organization:
- Walter Reed Army Medical Center, Washington, DC
- OSTI ID:
- 7110221
- Journal Information:
- J. Clin. Endocrinol. Metab.; (United States), Vol. 44:4
- Country of Publication:
- United States
- Language:
- English
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BETA DECAY RADIOISOTOPES
BODY
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
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550601* - Medicine- Unsealed Radionuclides in Diagnostics