Prolactin

Question 1

Prolactin release

Answer 1

Lactotrophs in anterior pituitary

Question 2

Prolactin role

Answer 2

Alveolar growth during adolescence
Stimulation of breast milk production
Suppresses synthesis + release of LH and FSH

Question 3

Prolactin controlled by

Answer 3

Under tonic inhibition by dopamine

TRH provides stimulating input

Question 4

Prolactin positive stimuli

Answer 4

Suckling stimulus
Sleep
Stress

Question 5

Prolactin negative stimuli

Answer 5

Negative feedback

Dopamine

Question 6

Prolactin acts on the

Answer 6

Mamillary gland

Question 7

Hyperprolactinaemia- Signs + symptoms

Answer 7

Oligo/amenorrhoea- prolactin inhibits LH and FSH secretion
Galactorrhoea- inappropriate production of breast milk
Pituitary adenoma signs- headache, visual disturbance (bitemporal hemianopia)

Question 8

Hyperprolactinaemia causes

Answer 8

Prolactinoma
Pituitary stalk compression
Drugs
Primary hypothyroidism
Pregnancy
Stress

Question 9

Prolactinoma types

Answer 9

Microprolactinoma (<1cm)

Macroprolactinoma (>1cm)

Question 10

Pituitary stalk compression

Answer 10

Loss of dopamine inhibition
Other pituitary adenoma
Trauma

Question 11

Drugs causing hyperprolactinaemia

Answer 11

Dopamine antagonists

Question 12

Primary hypothyroidism + hyperprolactinaemia

Answer 12

Causes increased TRH and TSH

–> increased prolactin

Question 13

Hyperprolactinaemia Investigations

Answer 13

Exclude pregnancy
Several blood samples to avoid false positive- raise due to stress-inducing venipuncture
Pituitary adenomas can also co-secrete GH- OGTT
MRI pituitary

Question 14

Hyperprolactinaemia- serum

Answer 14

Modestly elevated levels
High
Very high

Question 15

Hyperprolactinaemia- Modestly elevated levels

Answer 15

500-2000mU/L

Consider non-adenomatous causes- medications, stalk compression, hypothyroidism, stress

Question 16

Hyperprolactinaemia- High levels

Answer 16

> 3000 mU/L

Microadenoma

Question 17

Hyperprolactinaemia- Very high levels

Answer 17

> 6000 mU/L

Macroadenoma

Question 18

Hyperprolactinaemia Treatment Aims

Answer 18

Prevent inappropriate lactation
Restore fertility
Prevent bone demineralization due to reduced oestrogen

Question 19

Hyperprolactinaemia Treatment

Answer 19

Medical therapy- all prolactinomas should be treated with medical therapy in the first instance, even in presence of chiasm involvement or visual field loss
Surgery and radiotherapy very rarely required

Question 20

Hyperprolactinaemia Medical treatment

Answer 20

Prolactinomas positively sensitive to dopamine agonists
–> cabergoline, bromocriptine (worse nausea)
5 years treatment enough to cure most microprolactinomas
Larger prolactinomas usually require ongoing treatment