Abnormal thyroid stimulating hormone following pituitary surgery

Hyperthyroidism and acromegaly due to a thyrotropin- and growth hormone-secreting pituitary tumor. Lack of hormonal response to bromocriptine

A 47-year-old woman with acromegaly and hyperthyroidism was found to have an inappropriately normal serum thyrotropin level (1.5 to 2.5 microU/ml) that responded poorly to thyrotropin-releasing hormone but showed partial responsiveness to changes in circulating thyroid hormones. Serum alpha-subunit levels were high-normal and showed a normal response to thyrotropin-releasing hormone. Growth hormone and thyrotropin hypersecretion persisted despite radiotherapy and bromocriptine treatment. Selective trans-sphenoidal removal of a pituitary adenoma led to normalization of both growth hormone and thyrotropin levels. Both thyrotropes and somatotropes were demonstrated in the adenoma by the immunoperoxidase technique and electron microscopy.

Radioligand receptor assay for TSH and TSH-binding-inhibiting antibodies using solubilized TSH-receptor

A radioligand receptor assay (RRA) for TSH and TSH-binding-inhibiting antibodies (TBIAb) using solubilized receptor is presented. Introducing charcoal for separation of bound and free hormone has made the assay easier to handle. The detection limit for TSH is 30 microU/ml as measured by RIA. TBIAb was found in the sera of 19 of 26 hyperthyroid patients. Only 16 sera were positive when the RRA using membrane fragments was applied.