Adenomas of TSH-secreting cells in the pituitary (thyrotroph adenomas) may secrete sufficient TSH to cause thyrotoxicosis. One or all of growth hormone, prolactin and gonadotrophins may also be secreted by these tumours. Occasionally the pituitary is ΓÇÿresistantΓÇÖ to the feedback mechanism of thyroid hormone. TSH is then secreted ΓÇÿas thoughΓÇÖ there were hypothyroidism, which causes increased release of thyroxine and generalised thyrotoxicosis.
