In order to examine whether thyroid hormone concentration interfere with the thyroid gland responsivity to TSH, paired studies on the effect of short-term T3 treatment on T4 response to exogenous TSH ( 5 I.U. i.m.) were carried out in 10 euthyroid volunteers. During T3 administration ( 120 mcg/day for 4 days starting 48 hr before TSH injection) a significant decrease in T4 concentrations was observed both prior to and after TSH, with an inhibition of the T4 response ranging from 36-77% as calculated from the area under the response curve. The present data are in agreement with the existence of a "short-loop" thyroid-thyroid regulatory mechanism in man. In fact, the decreased percent rise of T4 after TSH suggests an inhibitory effect of T4 release following TSH, even though a modification of T4 kinetic parameters during T3 administration may account for a portion of the lowering of T4 blood concentrations.
The effect of short-term triiodothyronine administration on thyroxine response to exogenous TSH in man / R., Vigneri; S., Squatrito; V., Pezzino; Filetti, Sebastiano; P., Polosa. - In: THE JOURNAL OF CLINICAL ENDOCRINOLOGY AND METABOLISM. - ISSN 0021-972X. - STAMPA. - 41:5(1975), pp. 974-976. [10.1210/jcem-41-5-974]
The effect of short-term triiodothyronine administration on thyroxine response to exogenous TSH in man.
FILETTI, SEBASTIANO;
1975
Abstract
In order to examine whether thyroid hormone concentration interfere with the thyroid gland responsivity to TSH, paired studies on the effect of short-term T3 treatment on T4 response to exogenous TSH ( 5 I.U. i.m.) were carried out in 10 euthyroid volunteers. During T3 administration ( 120 mcg/day for 4 days starting 48 hr before TSH injection) a significant decrease in T4 concentrations was observed both prior to and after TSH, with an inhibition of the T4 response ranging from 36-77% as calculated from the area under the response curve. The present data are in agreement with the existence of a "short-loop" thyroid-thyroid regulatory mechanism in man. In fact, the decreased percent rise of T4 after TSH suggests an inhibitory effect of T4 release following TSH, even though a modification of T4 kinetic parameters during T3 administration may account for a portion of the lowering of T4 blood concentrations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.