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Hyperprolactinemia may result from

  1. Excess production from the pituitary, eg prolactinoma. (A prolactinoma is the most common hyperfunctioning pituitary adenoma).
  2. Administration of a dopamine antagonist 

(Galactorrhea is the spontaneous flow of milk from the breast, unassociated with childbirth or nursing. It is usually bilateral)


Causes of hyperprolactinemia

  1. Physiological: Pregnancy; breast-feeding; stress eg post-seizure.
  2. Drugs (most common cause): Phenothiazine; metoclopramide; haloperidol, methyldopa; estrogens.
  3. Diseases: Prolactinoma: micro- or macroadenoma;
    Stalk damage: pituitary adenomas, surgery, trauma; craniopharyngioma,;
  4. Other: hypothyroidism, CRF. 


  1. Amenorrhea          
  2. Oligomenorrhea;              
  3. visual field defect,      
  4. infertility;   
  5. Galactorrhea
  6. Men have decreased libido and erectile dysfunction and infertility, due to hypogonadism.
  7. Hypopituitarism occurs in 50% and it is caused by mass effect of the tumor 

Tests :

  1. Serum prolactin level estimation (It is the most important investigation)
​​a. If serum prolactin >100 microgram/ml it is strongly suggestive of macroadenoma. Levels more than 200 micro gram per ml occur only in prolactinoma.
  1. CT / MRI
    Diagnosis is by MRI/CT for confirmation of tumor.
    1. Microprolactinomas: A tumour <10mm on MRI
    2. Macroprolactinomas: A tumour> 10 mm diameter on MRI. 


  1. Bromocriptine, a dopamine agonist. PRL secretion, restores menstrual cycles and tumour size.
    An alternative dopamine agonist is cabergoline: more effective and less side effects.
  2. Trans-sphenoidal surgery
  3. Radiation therapy for non resectable macroadenomas 

Growth Hormone

Basic physiology

  1. Growth hormone is also known as somatotropin.
  2. Growth hormone releasing inhibitory factor (GHRIF) is also known as somatostatin.  
  3. Somatomedin (LQ 2012) are a group of hormone produced when stimulated by somatotropin (i.e. GH)  to mediate its effects. They are:
    1. Somatomedin A - also known as IGF – 2
    2. Somatomedin B - Derived from vitronectin
    3. Somatomedin C - also known as IGF – 1. It is a potent growth and differentiation factor.
  4. Increase GH release by occur by
    1. Fasting  
    2. i/v L arginine
    3. alpha agonist
    4. dopamine  
    5. apomorphine
    6. beta blocker 

Extra Edge:

  1. GH is released by GHRF  
  2. Ghrelin is agonist for GHRF so increases GH release.  
  3. Somatostatin inhibits GH secretion.
  4. GH exerts its action directly or via IGF-1
Recent Advances
Mecasermin is recombinant human insulin-like growth factor 1 (IGF-I), which is used for the long-term treatment of growth failure in children with severe primary IGF-I deficiency.
This drug is not to be confused with Mecasermin rinfabate, which is a combination of recombinant human IGF-1 (rhIGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3). IGFBP-3 serves to prolong the action of IGF-1 in the human body. These are the new drugs not goven in Harrison 18th edition also !!!

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