Calcitonin

Calcitonin

The parafollicular C cells of the thyroid are of neuroendocrine origin and arrive in the thyroid via the ultimobranchial body ( Figure 55.1 ). They produce calcitonin. Sir James Berry , 1860–1946, surgeon, Royal Free Hospital, London, UK. Oliver H Beahrs , 1914–2006, surgeon, Mayo Clinic, Rochester, MN, USA. Emil Zuckerkandl , 1849–1901, Austro-Hungarian anatomist, brother of urologist Otto Zuckerkandl. Myxoedema was first described in 1873 by Sir William Withey Gull, 1816–1890, physician, Guy’s Hospital, London, UK. Synthesis and release of thyroid hormones from the thyroid is controlled by thyroid-stimulating hormone (TSH) from the - anterior pituitary . Secretion of TSH depends upon the level of circulating thyroid hormones and is modified in a nega - tive feedback manner. In hyperthyroidism TSH production is suppressed, whereas in hypothyroidism it is stimulated. , Regulation of TSH secretion also results from the action of thyrotr ophin-releasing hormone (TRH) produced in the hypothalamus.

TABLE 55.1 Results of thyroid function tests in normal and pathological states. Thyroid functional state TSH (0.3–3.3 /uni00A0 mU/L) Euthyroid Normal Thyrotoxic Undetectable Myxoedema High Suppressive T therapy Undetectable 4 T toxicity Low/undetectable 3 T , tri-iodothyronine; T , L -thyroxine; TSH, thyroid-stimulating hormone. 3 4

Calcitonin

The parafollicular C cells of the thyroid are of neuroendocrine origin and arrive in the thyroid via the ultimobranchial body ( Figure 55.1 ). They produce calcitonin. Sir James Berry , 1860–1946, surgeon, Royal Free Hospital, London, UK. Oliver H Beahrs , 1914–2006, surgeon, Mayo Clinic, Rochester, MN, USA. Emil Zuckerkandl , 1849–1901, Austro-Hungarian anatomist, brother of urologist Otto Zuckerkandl. Myxoedema was first described in 1873 by Sir William Withey Gull, 1816–1890, physician, Guy’s Hospital, London, UK. Synthesis and release of thyroid hormones from the thyroid is controlled by thyroid-stimulating hormone (TSH) from the - anterior pituitary . Secretion of TSH depends upon the level of circulating thyroid hormones and is modified in a nega - tive feedback manner. In hyperthyroidism TSH production is suppressed, whereas in hypothyroidism it is stimulated. , Regulation of TSH secretion also results from the action of thyrotr ophin-releasing hormone (TRH) produced in the hypothalamus.

TABLE 55.1 Results of thyroid function tests in normal and pathological states. Thyroid functional state TSH (0.3–3.3 /uni00A0 mU/L) Euthyroid Normal Thyrotoxic Undetectable Myxoedema High Suppressive T therapy Undetectable 4 T toxicity Low/undetectable 3 T , tri-iodothyronine; T , L -thyroxine; TSH, thyroid-stimulating hormone. 3 4