Prolactin Flashcards
Where is prolactin produced?
Anterior pituitary gland, Decidualized endometrium, Myometrium
What is the main function of prolactin?
lactogenesis
True or false: In pregnancy prolactin is also responsible for amniotic fluid regulation?
True
What two hormones increase secretion of Prolactin from the anterior pituitary?
estrogen and thyroid releasing hormone
Prolactin stimulates _____ and _____
Breast growth and lactation
During pregnancy, lactation is inhibited by _____
Progesterone
What hormone triggers ejection of milk/let down during lactation?
oxytocin
Oxytocin release is triggered by ____.
Nipple stimulation
Failure to lactate within 7 days after delivery may be the first sign of what syndrome?
Sheehan’s syndrome
What causes Sheehan’s syndrome?
Infarct of the pituitary gland leading to hypopituitarism
What is the main hormone responsible for blocking the secretion of prolactin?
Dopamine
Galactorrhea is due to increased _______
Prolactin
What percent of women with Galactorrhea will have elevated prolactin?
33%
What medications can cause Galactorrhea?
Dopamine receptor blockers ( Antipsychotics, metoclopramide, SSRIs, TCAs), Dopamine depleting agents (Methyldopa, Reserpine), Dopamine release inhibitors (Opiates, Cimetidine)
What types of tumors can cause Galactorrhea?
Prolactinoma in the pituitary gland
What other symptoms are associated with Macroprolactinomas?
visual field defects, headaches
What other metabolic syndrome can cause galactorrhea and by what mechanism?
Hypothyroidism, increased TRH
Hypothalamic lesions that block or compress the stalk cause galactorrhea by what mechanism?
Block delivery of dopamine to the anterior pituitary
Hyperprolactinemia causes what change in the menstrual cycle?
most often causes amenorrhea
What is the mechanism of action by which high levels of prolactin interfere with the menstrual cycle?
inhibits pulsatile secretion of GnRH
What tests should be performed when evaluating a patient with Galactorrhea?
pregnancy test, serum prolactin
What tests should be done if prolactin is elevated?
MRI with gadolinium of brain and pituitary
What is the normal level of serum Prolactin in non pregnant state
< 25 ng/ml
What is the normal level of serum prolactin in the pregnant state?
400 ng/ml
What is the definition of microadenoma
< 1 cm
What class of medication are highly effective at treating hyperprolactinemia?
Dopamine agonists
What are two examples of dopamine agonists?
Bromocriptine, Cabergoline
What is the starting dose of bromocriptine and how should it be titrated?
Start with 2.5mg at bedtime, titrate until menses achieved and prolactin levels normalize
what are common side effects of bromocriptine?
nausea, headache, orthostatic hypotension
How can bromocriptine be administered to decrease side effects?
vaginally
How should microadenomas be managed?
dopamine agonist, repeat prolactin and imaging q 2 years
When should you offer surgery for macroadenomas?
With failed medical management and persistent CNS symptoms
What is the treatment for a woman at 20 weeks gestation who has bothersome galactorrhea and growth in her microprolactinoma?
Bromocriptine
