Effects of the Administration of L-Thyroxine on the Levels of TSH and Long-acting Thyroid Stimulator (L.A.T.S.) in the Serum of the Thyroid Patients

Abstract

The effects of administration of T₄ on the levels of TSH and L.A.T.S. were studied in 4 hypothyroid and 3 hyperthyroid patients.
The activities of TSH and L.A.T.S. in the serum were determined by our modification of the method of McKenzie.
In all hypothyroid cases, the TSH activities were reduced significantly with an increase of PBI concentration, following intramuscular administration of 1mg of T₄ daily for two days. On the contrary the L.A.T.S. activities did not decrease at all despite of a rise of PBI level. Particularly the fact is noteworthy that not only the 12 hours' activity of L.A.T.S. but also the 2 hours' were not suppressed significantly.
In the immunological demonstration too, we found that anti-TSH serum was capable of neutralizing neither the 2 hours' activity of L.A.T.S. nor the 12 hours'.