II. Physiology

  1. See Thyroid Physiology
  2. Thyroid Stimulating Hormone (TSH) is a glycoprotein synthesized in the Basophil cells of the anterior pituitary
  3. Regulation
    1. Positive Stimulation
      1. Thyroid Releasing Hormone (TRH, Thyrotopin Releasing Hormone, from Hypothalamus)
    2. Negative feedback
      1. Unbound Thyroxine (Free T4)
      2. Unbound Triiodothyronine (Free T3)
  4. Thyroid Stimulating Hormone (TSH) promotes all aspects of Thyroid Hormone production
    1. Increases iodide uptake
    2. Incorporation of Iodine into Thyroglobulin
    3. Thyroglobulin lysis into active Thyroid Hormones T4 and T3
    4. Stimulates proliferation of increased Thyroglobulin synthesizing cells (Cuboidal cells) in Thyroid follicles
  5. Variation
    1. TSH levels follow a circadian rhythm
      1. TSH will vary as much as 1-2 uIU/ml over the course of the day
      2. Consider drawing TSH at the same time of day for longterm serial measurements
    2. TSH levels increase with normal aging in euthyroid patients
      1. Consider using age-adjusted TSH interpretation
      2. Age 20-29: 3.56 mIU/ml is 97th percentile
      3. Age >80: 7.49 mIU/ml is 97th percentile
      4. Surks (2007) JCEM 92: 4575 [PubMed]
    3. Pregnancy
      1. See Thyroid Dysfunction in Pregnancy
      2. See Hypothyroidism in Pregnancy
      3. Maintaining euthyroid state in pregnancy is critical
    4. Euthyroid individuals still have considerable variation in TSH levels over time
    5. Populations of euthyroid individuals also have considerable variation in TSH levels

III. Interpretation: Non-Pregnant

  1. Normal
    1. Random: 0.3 - 5.0 uIU/ml
    2. Following Thyroid Releasing Hormone (TRH) stimulation
      1. TSH: 9-30 uIU/ml at 20-30 min
  2. Borderline Increased: 5-10 uIU/ml
  3. High: >10 uIU/ml

IV. Interpretation: Pregnancy

  1. Non-pregnanct: 0.3 to 4.3 mIU/ml
  2. First trimester: 0.1 to 2.5 mIU/ml
  3. Second trimester: 0.2 to 3.0 mIU/ml
  4. Third timester: 0.3 to 3.0 mIU/ml
  5. Abbassi (2010) Obstet Gynecol 114(6): 1326-31 [PubMed]

V. Causes: Increased TSH

  1. Hypothyroidism
  2. Drugs
    1. Amiodarone
    2. Lithium
    3. Haloperidol
    4. Chlorpromazine
    5. Metoclopramide
    6. Metyrapone
    7. Domperidone
  3. TSH antibodies
  4. Pituitary resistance
  5. Thyrotropin Releasing Hormone (TRH) Secreting Tumor
  6. Acute illness (esp. elderly)
    1. Wong (1981) Arch Intern Med 141(7):873-5 +PMID: 7235805 [PubMed]

VI. Causes: Decreased TSH

  1. Hyperthyroidism
  2. Euthyroid Sick Syndrome (associated with acute illness)
  3. Central Hypothyroidism
    1. Hypopituitarism or Pituitary Ademoma causing TSH deficiency and low T4 and T3
  4. Hyponatremia
  5. Malnutrition
  6. Mood Disorders
  7. Medications
    1. Amiodarone
    2. Interferon
    3. Interleukin-2
    4. Opiates
    5. Corticosteroids
    6. Levothyroxine
    7. Levodopa
    8. Dopamine Agonists
    9. Pyridoxine
    10. Bromocriptine
    11. Somatostatin analogs
    12. Carbemazepine
    13. Metformin
    14. Biotin (High dose, >5000 mcg/day)

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Related Studies

Ontology: Thyrotropin (C0040160)

Definition (NCI_NCI-GLOSS) A hormone produced by the pituitary gland. TSH stimulates the release of thyroid hormone from thyroglobulin. It also stimulates the growth of thyroid follicular cells. An abnormal TSH level may mean that the thyroid hormonal regulation system is out of control, usually as a result of a benign condition (hyperthyroidism or hypothyroidism).
Definition (NCI) A peptide hormone secreted by the anterior pituitary. It promotes the growth of the thyroid gland and stimulates the synthesis of thyroid hormones and the release of thyroxine by the thyroid gland.
Definition (MSH) A glycoprotein hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Thyrotropin stimulates THYROID GLAND by increasing the iodide transport, synthesis and release of thyroid hormones (THYROXINE and TRIIODOTHYRONINE). Thyrotropin consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the pituitary glycoprotein hormones (TSH; LUTEINIZING HORMONE and FSH), but the beta subunit is unique and confers its biological specificity.
Definition (CSP) glycoprotein hormone of the anterior pituitary that promotes the growth of, sustains, and stimulates hormonal secretion of the thyroid gland.
Concepts Pharmacologic Substance (T121) , Hormone (T125) , Amino Acid, Peptide, or Protein (T116)
MSH D013972
SnomedCT 24096000, 65428006, 326013007
LNC LP14487-0, MTHU002328
English Hormone, Thyroid-Stimulating, Thyreotropin, Thyroid-Stimulating Hormone, Thyrotrophin, Thyrotropin, Thyrotrophic hormone product, TSH - Thyroid stimulating hormone, TSH-Thyroid stim horm, Thyroid Stimulating Hormone, Thyrotropin [Chemical/Ingredient], thyroid stimulating hormone (TSH), thyrotropic hormone, thyroid stimulating hormone, thyrotropin, Thyrotropic hormone preparation, Thyrotropic hormone preparation (product), TSH preparation, THYROTROPIN, TSH (Thyroid Stimulating Hormone), Thyreotrophic Hormone, thyroid-stimulating hormone, Thyrotropic Hormone, TSH, Thyroid stimulating hormone, Thyrotrophin product, Thyroid stimulating hormone (substance), Thyrotrophin product (product), Thyrotrophin product (substance), Thyrotropic hormone preparation (substance)
Portuguese Hormônio Tireoestimulante, Tireotropina, Hormônio Estimulante da Glândula Tireoide, Hormônio Estimulante da Tireoide, Tireotrofina, Tirotropina, Tirotrofina
Swedish Tyreotropin
Czech tyreoideu stimulující hormon, TSH, tyreotropin, thyreotropin
Finnish Tyreotropiini
French TSH (Thyroid-stimulating hormone), Thyréotrophine, Thyréostimuline, Thyréotropine, Thyrotropine, Thyrotrophine, Hormone thyréotrope
Japanese 甲状腺刺激ホルモン, チトロパール, チロトロピン, サイロトロピン
Spanish tirotrofina, producto (producto), tirotrofina (producto), tirotrofina, producto, preparado de tirotrofina, preparado de hormona tirotrópica, preparado de hormona tirotrófica, preparado de TSH, preparado de hormona tirotrófica (producto), hormona estimulante tiroidea, hormona tiroideoestimulante, preparado de hormona tirotrófica (sustancia), tirotrofina (sustancia), tirotrofina, tirotropina, Tirotropina, Hormona Estimulante de la Tiroides
Italian Tireotropina, TSH (Ormone stimolante la tiroide), Ormone stimolante la tiroide, Tirotropina
Polish Tyreotropina, Hormon tyreotropowy, TSH
Norwegian TSH, Thyreoideastimulerende hormon, Tyreotropin, Tyrotropin
German Thyreoidea-stimulierendes Hormon, Thyreotropin, TSH (Thyreoidea-stimulierendes Hormon)