Abstract
Thyroidal suppressibility after oral administration of a single dose of 3 mg l-T4 and after multiple daily doses of l-T3 proved to be equivalent. There were no clinical disturbances during the l-T4 suppression test. Radioimmunoassay of T3 and T4 showed extreme elevations of serum T3 up to 10.05 ng/ml during the classical T3 suppression test, while in the l-T4 test initial serum T4 peaks of 220–390 ng/ml were correlated with only minor serum T3 elevations of about 1.00 ng/ml above baseline levels. It seems evident that this practicable T4 suppression test is less hazardous than the usual T3 suppression test.

This publication has 0 references indexed in Scilit: