TSH reserve was determined by means of the TRH stimulation test in 18 cases with various endocrine diseases. In 2 cases of primary hypothyroidism the basal level of TSH was higher than normal and the response to TRH was prompt and significant. Four of 5 cases with secondary hypothyroidism had normal basal levels of TSH, while in the fifth TSH was slightly decreased. Four of these cases showed a significant increase in TSH after TRH stimulation (tertiary hypothyroidism) but in 1 case there was no response (secondary hypothyroidism). In 3 acromegalic patients the basal level of TSH was normal but there was no response to TRH stimulation. In 2 cases with an enlarged sella turcica but no endocrine symptoms the basal level of TSH was normal in one and slightly decreased in the other, while the response to TRH stimulation was positive in only one. In 3 cases of gonadal dysgenesis with high levels of gonadotropins TSH was within the normal range and there was a significant response to TRH stimulation, which was slightly lower in patients who had been on long term substitution therapy with estrogens.
|Published - 1976