pituitary

Question 1

2 physiological causes of prolactin release

Answer 1

pregnancy, breastfeeding

Question 2

pathological cause of prolactin release

Answer 2

prolactinoma (microadenoma < 10mm diameter); most common functioning pituitary tumour

Question 3

effect of high prolactin on GnRH

Answer 3

suppressed pulsatility, so affects gonads

Question 4

4 presentations of hyperprolactinaemia due to pituitary adenoma in women

Answer 4

galactorrhoea (milk production), secondary amenorrhoea (or oligomenorrhoea), loss of libido, infertility

Question 5

4 presentations of hyperprolactinaemia due to pituitary adenoma in men

Answer 5

galactorhoea uncommon but can occur (as appropriate steroid background (oestrogen) usually inadequate), loss of libido, erectile dysfunction, infertility

Question 6

how is prolactin secretion regulated

Answer 6

anterior pituitary lactotroph secrete prolactin; has inhibitory regulation as prolactin release inhibited by release of dopamine from hypothalmic dopaminergic neurones, which bind to D2 receptors on anterior pituitary lactotrophs

Question 7

treatment for hyperprolactinaemia

Answer 7

D2 receptor agonist (polypeptide e.g. bromocriptine, cabergoline), which decreases prolactin secretion and reduces tumour size; oral administration

Question 8

5 side effects of dopamine receptor agonists

Answer 8

nausea and vomiting, postural hypotension, dyskinesias (impaired voluntary movement), depression, impulse control disorder e.g. pathological gambling, hypersexuality (activation of reward system)

Question 9

what other disease can dopamine agonists help treat

Answer 9

Parkinson’s disease