Categories: Endocrinology

Hyperprolactinemia and Hypothyroidism: Mechanism

Hyperprolactinemia is one of the most common endocrine disorders in the hypothalamic- pituitary axis. Although the most common etiologies of hyperprolactinemia are iatrogenic and prolactin producing adenoma (prolactinoma) — Another possible cause is primary hypothyroidism.

HOW? Secretion of Prolactin is primarily controlled by prolactin inhibitory hormone (dopamine) from the hypothalamus, however other factors [i.e VIP and Thyroid releasing hormone (TRH)] can influence its release. 

  • TRH is a hypothalamic tripeptide that sits atop the hypothalamic/pituitary/thyroid axis; its primary function is stimulating release of thyrotropin (TSH) from the anterior pituitary gland. However it can also cause an increase in prolactin (PRL) secretion!


  1. Surks MI, Ortiz E, Daniels GH, Sawin CT, Col NF, Cobin RH, Franklyn JA, Hershman JM, Burman KD, Denke MA, Gorman C, Cooper RS, Weissman NJ. Subclinical thyroid disease: scientific review and guidelines for diagnosis and management. JAMA. 2004 Jan 14; 291(2):228-38.
  2. Hinkle et al. Desensitization, trafficking, and resensitization of the pituitary thyrotropin-releasing hormone receptor. Front. Neurosci., 13 December 2012 |
  3. Bahar A, Akha O, Kashi Z, Vesgari Z. Hyperprolactinemia in association with subclinical hypothyroidism . Caspian Journal of Internal Medicine. 2011;2(2):229-233.
  4. Dragana J, Xiangbing W. Primary Hypothyroidism Associated with Hyperprolactinemia and Pituitary Macroadenoma. Thyroid Science 6 (10): CR1-4, 2011
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Dr. C Humphreys

Internal Medicine

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