gonads

Question 1

hypothalamo-pituitary prolactin axis

Answer 1

hypothalamus -> high TRH and low dopamine secretion -> anterior pituitary -> prolactin -> lactation (dopamine released from hypothalamus exerts negative control on anterior pituitary, stopping prolactin release)

Question 2

effect of prolactin on GnRH pulsatility and LH actions on ovary/testes

Answer 2

inhibits GnRH pulsatility (pulsatility required for fertility) and inhibits LH actions on ovary/testes

Question 3

7 causes of hyperprolactinaemia

Answer 3

dopamine antagonist drugs; prolactinoma (usually benign; pituitary MRI); stalk compression due to pituitary adenoma (stops dopamine coming down; pituitary MRI); PCOS (polycystic ovary syndrome); hypothyroidism; oestrogens (OCP), pregnancy, lactation; idiopathic

Question 4

2 types of dopamine antagonist drugs that can cause hyperprolactinaemia

Answer 4

anti-emetics (metoclopramide), anti-psychotics (phenothiazines)

Question 5

2 clinical features of hyperprolactinaemia

Answer 5

galactorrhoea, reduced GnRH secretion and LH action leading to secondary hypogonadism (low LH, low FSH, low oestradiol)

Question 6

2 clinical features of hyperprolactinaemia caused by a prolactinoma

Answer 6

headache, visual field defect

Question 7

treatment for hyperprolactinaemia caused by dopamine antagonists

Answer 7

treat cause and stop drugs

Question 8

general drug treatment for hyperprolactinaemia

Answer 8

dopamine agonist e.g. bromocriptine, cabergoline (very potent; treats hyerprolactinaemia and shrinks prolactinoma)

Question 9

2 treatments for hyperprolactinaemia caused by prolactinoma

Answer 9

dopamine agonist therapy, pituitary surgery rarely needed