T1 L15:LACTATION AND Galactorrhoea & PROLACTINOMAS Flashcards
what is milk composed of
6marks
Sugar
Lactose & oligosaccharides
Milk fats
triglycerides, cholesterol, phospholipids, steroid hormones
Proteins
Caseins, lactalbumin, lactoferrin, secretory IgA, lysozyme
Minerals
Na, K, Cl, Ca, Mg, Phosphate
Growth factors
Cellular components (esp in colostrum)
Macrophages, lymphocytes, neutrophils, epithelial cells
Phospholipids (membrane fragments)
what type of feedback loop is Lactation (galactopoiesis)
and through which signalling factors
Positive feedback loops
Regular removal of milk
Nipple stimulation
Prolactin (anterior pituitary)
Oxytocin (posterior pituitary)
what cells produce prolactin
and mechanism
Lactotroph cells
similar to GH, similar receptors to GH
mechanism is via:
- Tyrosine phosphorylation
- JAK-STAT signalling
what is prolactin release inhibited by
dopamine
what chemical is prolactin release stimulated by
Serotonin
TRH
oxytocin
what extended period of time does Prolactin release increase
during pregnancy
what is lactational amenorrhoea
when someone lactates they don’t have menstrual periods
why-
increased prolactin causes decreased:
GnRH
LH and FSH, pulsatility
oestrogen / testosterone
where is oxytocin synthesised
hypothalamic magnicellular neurons - in the posterior pituitary -
- Neurosecretory granules released into the capillary system
- supraoptic and paracentricular nucleus
what does oxytocin cause
increased:
+ uterine myometrial contraction at birth
+ smooth muscle activation in breast
‘myoepithelial contraction’
+ milk let-down
What causes milk production/initiation
lactogenesis
- progesterone
- pregnancy
- Colostrum
what biochemical factors causes secretory activation
- low progesterone/oestrogen
- high prolactin (cortisol,insulin)
- copious milk production after delivery
- —-2-3 days post-partum
what are the effects of prolactin on GnRH, LH FSH and oestrogen/testosterone
decreases all of them
what is the presentation of hyperprolactinaemia
Men-
- usually have visual symptoms
- don’t produce milk
- have erectile dysfunction
- decreased libido
women-
- amenorrhoea
- galactorrhoea
- present after stopping the pill
difference between micro and macro
cm bounds
what are the causes of hyperprolactinaemia
Physiological- preg and lactation
Drugs
Polycystic ovarian syndrome
Hypothalamic-pituitary disease- icro/macroPRLoma
& non-functioning adenoma
what drugs can increase prolactinaemia
-Antidepressants and anti-psychotics
—(they inhibit secretion and action of dopamine )
—Stimulation of serotonin pathways
Drugs used for nausea and vertigo
-phenothiazines
-metoclopramide -antag d2 receptors
what investigations can you do
- pregnancy test
- renal function
- liver function tests
what are the aims of treatment
- Restore fertility
- stop galactorrhoea
- Restore menstrual periods
- Shrink tumour
How do you manage a PRLoma
MEDICAL’
Dopaminergic drugs
-Cabergoline
-(Bromocriptine)
Preserve pituitary function
Side-effects -RARE: --Fibrotic reactions -Pulmonary, --pericardial, retroperitoneal --Psychiatric disturbances
PRLoma management for MicroPRlomas
&
Idiopathic hyperPRLaemia
MicroPRLomas
Can take COCP / HRT if fertility not required
Can discontinue treatmment in pregnancy
May involute post-partum
Can trial withdrawal of treatment after ~ 2 years (may not recur)
‘Idiopathic hyperPRLaemia’
Assumed to be a microPRLoma too small to be detected radiologically
NFA (pituitary adenoma) management
Surgery & radiotherapy
risks loss of pituitary function
Look at cases and use this info to do quiz
How did it go?
