15. Lactation and Prolactinomas

Question 1

breast development in puberty

Answer 1

oestrogen, progesterone
GH (via IGF-1)
increase alveolar buds and lobules

Question 2

breast development in pregnancy

Answer 2

oestrogen, progesterone 
hCG, prolactin 
alveolar development: increased ducts and lobules 
differentiated secretory units
colostrum accumulates

Question 3

milk production: secretory initiation

Answer 3

progesterone
occurs during pregnancy
colostrum

Question 4

milk production: sensory activation

Answer 4

secreted progesterone/oestrogen
increased prolactin (cortisol, insulin)
copious milk production after delivery (usually 2-3 days)

Question 5

milk composition

Answer 5

sugar 
milk fats 
proteins 
minerals 
growth factors 
cellular factors, esp. in colostrum

Question 6

sugars in milk

Answer 6

lactose

oligosaccharides

Question 7

fats in milk

Answer 7

triglycerides
cholesterol
phospholipids
steroid hormones

Question 8

proteins in milk

Answer 8

casins
lactalbumin 
lactoferrin 
secretory IgA 
lysozyme

Question 9

minerals in milk

Answer 9

Na+
K+
Cl-
Mg2+
PO4-

Question 10

cellular components in milk

Answer 10

macrophages 
lymphocytes 
neutrophils 
epithelial cells 
phospholipids

Question 11

lactation

Answer 11

galactopoiesis
positive feedback
regular removal of milk, nipple stimulation
prolactin (from ant pituitary), oxytocin (from post pituitary)

Question 12

prolactin

Answer 12

secreted by lactotroph cells in anterior pituitary
similar GH with similar receptor (tyrosine phosphorylation, JAK-STAT)
release is inhibited by dopamine
release is stimulated by serotonin, TRH and oxytocin

Question 13

lactational amenorrhoea

Answer 13

contraceptive efficacy depends on frequency and duration of breast feeding

Question 14

what can increased prolactin cause?

Answer 14

decreased GnRH
decreased LH and FSG (decreased pulsatility)
decreased oestrogen/testosterone

Question 15

oxytocin

Answer 15

nonapeptide
synthesised in hypothalamic magnicellular neurons
released from posterior pituitary
neurosecretory granules released into capillary system of post pituitary

Question 16

roles of oxytocin

Answer 16

uterine myometrial contraction at birth
smooth muscle activation in breast
milk let down: role in maternal behaviour?

Question 17

evolutionary perspective of lactation

Answer 17

mammals lactate: production of nutritious secretion from an exocrine gland
continued nurture of offspring after birth - enhanced brain development

Question 18

hyperprolactinaemia presentation in women

Answer 18

oligo/amenorrhoea
galactorrhoea
subfertility
may not have all symptoms

Question 19

hyperprolactinaemia presentation in men

Answer 19

erectile duysfincttion
decreased libido 
visual symptoms, headaches 
hypopituitarism 
galactorrhoea/gynaecomastia

Question 20

causes of hyperprolactinaemia

Answer 20

physiological - pregnancy, lactation
hypothalamic-pituitary disease (prolactinoma, non-functioning adenoma)
drugs
stress
other - PCOS, hypothyroidism, renal failure, cirrhosis

Question 21

drugs increasing prolactin secretion

Answer 21

antidepressants
antipsychotics
drugs for nausea/vertigo (phenothiazines, metoclopramide)

Question 22

drug mechanisms for increasing prolactin secretion

Answer 22

inhibition of secretion/action of dopamine

stimulation of central serotonin pathways

Question 23

hyperprolactinaemia investigations

Answer 23

pregnancy test 
renal function 
liver function tests 
thyroid function 
prolactin 
LH, FSH
testosterone
MRI pituitary

Question 24

aims of hyperprolactinaemia treatment

Answer 24

restore fertility
stop galactorrhea
restore regular menstrual periods/libido
shrink tumour

Question 25

prolactinoma management

Answer 25

dopaminergic drugs

preserve pituitary function

Question 26

microprolactinomas

Answer 26

can take COCP/HRT if fertility not required

discontinue treatment in pregnancy

Question 27

idiopathic hyperprolactinaemia

Answer 27

assumed to be a microprolactinoma too small to be detected radiologically

Question 28

non-functioning pituitary adenoma (NFA)

Answer 28

compression of pituitary stalk: disconnection hyperprolactinaemia
may need surgery/radiotherapy (space occupying effects)
prolactin will decrease with dopaminergic drugs
monitor MRI scan and visual fields