prolactin Flashcards
What hormone released by the hypothalamus regulates prolactin secretion?
Dopamine acts to suppress prolactin release
What 3 factors stimulate prolactin release?
Oestrogen (during pregnancy particularly), thyrotropin releasing hormone (TRH) from hypothalamus, nipple stimulation (reduced dopamine inhibition)
What are the functions of prolactin?
Promote milk production in the mammary glands after birth, develop the mammary glands during pregnancy/puberty
How does breastfeeding cause temporary infertility?
Prolactin inhibits GnRH secretion, which suppresses ovulation (lactational amenorrhoea)
What is the postive feedback loop for prolactin release?
Prolactin causes lactogenesis, which leads to infant suckling which positively feeds back for more prolactin release
What condition is caused by excess prolactin?
hyperprolactinaemia
What are the causes of hyperprolactinaemia?
prolactinoma (pituitary tumor), hypothyroidism (excess TRH), pituitary stalk compression
What are the symptoms of hyperprolactinaemia in females?
ameorrhoea, galactorrhea, infertility, reduced libido
What are the symptoms of hyperprolactinaemia in males?
erectile dysfunction, infertility, hypogonadism, gynaecomastia
What are investigations used to diagnose hyperprolactinaemia?
Bloods show elevated prolactin, high TRH if cause is hypothyroidism, MRI/Ct may show tumour
What are the non-pharmacological treatments of hyperprolactinaemia?
Surgery/radiation to remove prolactinoma
What are the pharmacological treatments of hyperprolactinaemia?
Dopamine agonists (bromocriptine)
What is the condition caused by deficency of prolactin?
hypoprolactinaemia
What are the causes of hypoprolactinaemia?
pituitary damage, postpartum pituitary necrosis (Sheehan’s syndrome)
What is Sheehan’s Syndrome?
Prolactin deficiency due to postpartum pituitary infarction caused by hypovolaemic shock from blood loss in childbirth.
