Effects of Oral Thyrotropin-Releasing Hormone, Exogenous Thyroid-Stimulating Hormone, and Withdrawal of Triiodothyronine on131I Uptake after Subtotal Thyroidectomy
- 1 March 1980
- journal article
- research article
- Published by The Endocrine Society in Journal of Clinical Endocrinology & Metabolism
- Vol. 50 (3) , 502-506
- https://doi.org/10.1210/jcem-50-3-502
Abstract
To characterize the effects of oral TRH [thyrotropin-releasing hormone, thyroliberin], exogenous TSH [thyroid-stimulating hormone, thyrotropin] and length of time of T3 [triiodothyronine] withdrawal on 131I uptake, 16 patients who had undergone subtotal thyroidectomy for differentiated thyroid cancer were administered T3 (75-100 .mu.g/day) for 8-15 wk before 131I remnant ablation. T3 was withdrawn for 10 days in 8 patients (group 1) and for 24 days in 8 patients (group 2) before a baseline 24-h 131I uptake (study day 2), with repeat uptakes (study days 5 and 7) after the sequential administration of oral TRH (80 mg 3 times a day for 3 days) and after bovine TSH (10 U [unit] i.m. each day for 2 days). Baseline serum TSH values were 30 .+-. 8 .mu.U/ml in group 1 and 73 .+-. 14 in group 2 (P < 0.02), and the values did not increase at the end of the study (day 7; 36 .+-. 9 and 77 .+-. 12, respectively). Four hours after doses 1 and 7 of oral TRH, changes in serum TSH values were 10 .+-. 4 and 9 .+-. 2 in group 1, respectively, and 17 .+-. 6 and 10 .+-. 3 in group 2, respectively. The 131I uptake increased 2.8 .+-. 0.7% after oral TRH in group 1 (an incremental rise of 70 .+-. 14%). There was no further increase of uptake after bovine TSH in group 1 and no increase in the uptake in group 2 after oral TRH or bovine TSH. Apparently 14 days of T3 withdrawal combined with 3 days of oral TRH administration during the latter portion induce I-concentrating capability equivalent to 24 days of T3 withdrawal, and this is not further augmented by bovine TSH administration at either time. This regimen should be satisfactory for remnant ablation and imaging purposes. Additional studies in patients with metastatic disease will be necessary to assess the effectiveness on whole body and tumor I retention.This publication has 0 references indexed in Scilit: