The secretion of thyrotrophin with impaired biological activity in patients with hypothalamic-pituitary disease.
We describe here two patients with hypothyroidism due to pituitary-hypothalamic disease in whom basal thyrotrophin (TSH) levels measured by radioimmunoassay (RIA) were elevated yet when measured by a cytochemical bioassay (CBA) were found to be normal. This finding and the absence of the normal rise of thyroid hormones in response to thyrotrophin-releasing hormone (TRH) mediated release of TSH confirms for the first time the secretion of TSH with impaired biological activity. Primary thyroid disease as a cause for the elevated immunoreactive TSH was excluded by the absence of circulating thyroid antibodies and by a normal thyroidal radioiodine uptake response to exogenous TSH.
D000328:Adult; D001681:Biological Assay; D005260:Female; D006651:Histocytochemistry; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D013972:Thyrotropin / Q000097:blood / Q000378:metabolism*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine