[New elements in the diagnosis and treatment of thyrotropic pituitary adenomas with hyperthyroidism].

Although thyrotropin-secreting pituitary tumors are rather exceptional, the authors have studied 5 new cases from 1982 to 1988. This apparently growing pattern is due to a more accurate diagnosis because of new laboratory measurements: --Immunoradiometric assay (IRMA) of ultra-sensitive thyrotropin (TSH); --Radioimmunoassay (RIA) of free alpha subunit of TSH; --Molar ratio of free alpha subunit/TSH before and after TRH stimulation; --Morphologic assessment of pituitary adenoma by computed tomographic scanning and nuclear magnetic resonance imaging; --Characterization of thyrotropin-secreting cells by immunohistochemical technics and identification of secretion products in cultured cells. The authors illustrate these new topics with a case report harboring a partial resistance to thyroid hormones.

[The syndrome of tissue resistance to thyroid hormones].

Known since 1967 and usually familial, the syndrome of tissue resistance to thyroid hormones may take one of two different forms, depending on the receptors involved. When resistance affects both peripheral and pituitary receptors, plasma thyroid hormone levels are high despite the lack of thyrotoxicosis, thyroxine and triiodothyronine are ineffective, even in high dosage, and plasma TSH increases to explode under TRH. When resistance only affects pituitary receptors, there is moderate thyrotoxicosis with paradoxical and inappropriate TSH increase.