Correlation between thyroid stimulators and 3, 5, 3′-triiodothyronine suppressibility in patients during treatment for hyperthyroidism with thionamide drugs …

N KUZUYA, C CHENG, H IKEDA… - The Journal of …, 1979 - academic.oup.com
N KUZUYA, C CHENG, H IKEDA, H UCHIMURA, K ITO, S NAGATAKI
The Journal of Clinical Endocrinology & Metabolism, 1979academic.oup.com
Abnormal thyroid stimulators have been identified in the sera of patients with Graves'
disease; however, there is little information regarding changes in thyroid stimulators during
thionamide treatment. The present studies were performed to observe changes in thyroid
stimulators assayed by thyroid-stimulating activity (TSI) and TSH-displacing activity (TDI)
during thionamide therapy. Thirty-three Graves' disease patients were studied; 16 were
untreated and 17 received thionamide therapy, during which 8 were T3 nonsuppressible …
Abstract
Abnormal thyroid stimulators have been identified in the sera of patients with Graves' disease; however, there is little information regarding changes in thyroid stimulators during thionamide treatment. The present studies were performed to observe changes in thyroid stimulators assayed by thyroid-stimulating activity (TSI) and TSH-displacing activity (TDI) during thionamide therapy. Thirty-three Graves' disease patients were studied; 16 were untreated and 17 received thionamide therapy, during which 8 were T3 nonsuppressible and 9 were T3 suppressible. The latter 17 patients had been treated for at least 1 yr and were euthyroid at the time of investigation. Immunoglobulin G (IgG) was concentrated using Protein-ASepharose affinity chromatography. Both IgGs with TSI and TDI were determined in each IgG. TSI was measured by the increase in cAMP concentrations in normal human thyroid slices incubated for 2 h with 10 mg IgG in 0.5 ml Krebs-Ringer bicarbonate buffer. TDI was determined by the radioligand receptor assay for TSH using 4 mg IgG/200 μl. Values in both assays were expressed as a percentage of those obtained using pooled normal IgG. The normal range was determined from values in 10 normal subjects. In untreated patients, TSI was positive in 13 out of 16 (81%), whereas 10 of the 16 showed positive results for TDI (63%). There was no significant correlation between values for TSI and TDI in untreated patients. During therapy, a significant difference in the incidence of TDI between T3-suppressible and T3-nonsuppressible patients was observed. TDI was positive in 4 of 8 nonsuppressible patients and in none of 9 suppressible patients. In contrast with TDI, TSI was negative in all patients during therapy regardless of their T3 suppressibility. In conclusion, 1) a dissociation exists between values for TSI and TDI in both untreated and thionamidetreated Graves' disease patients, and 2) TDI correlates with T3 suppressibility, whereas, TSI disappears before T3 suppressibility occurs. (J Clin Endocrinol Metab48: 706, 1979)
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