T1 L15:LACTATION AND Galactorrhoea & PROLACTINOMAS

Question 1

what is milk composed of

6marks

Answer 1

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)

Question 2

what type of feedback loop is Lactation (galactopoiesis)

and through which signalling factors

Answer 2

Positive feedback loops

Regular removal of milk
Nipple stimulation

Prolactin (anterior pituitary)
Oxytocin (posterior pituitary)

Question 3

what cells produce prolactin

and mechanism

Answer 3

Lactotroph cells

similar to GH, similar receptors to GH

mechanism is via:

• Tyrosine phosphorylation
• JAK-STAT signalling

Question 4

what is prolactin release inhibited by

Answer 4

dopamine

Question 5

what chemical is prolactin release stimulated by

Answer 5

Serotonin

TRH

oxytocin

Question 6

what extended period of time does Prolactin release increase

Answer 6

during pregnancy

Question 7

what is lactational amenorrhoea

Answer 7

when someone lactates they don’t have menstrual periods

why-

increased prolactin causes decreased:
GnRH
 LH and FSH,  pulsatility
 oestrogen / testosterone

Question 8

where is oxytocin synthesised

Answer 8

hypothalamic magnicellular neurons - in the posterior pituitary -

• Neurosecretory granules released into the capillary system
• supraoptic and paracentricular nucleus

Question 9

what does oxytocin cause

Answer 9

increased:

+ uterine myometrial contraction at birth

+ smooth muscle activation in breast
‘myoepithelial contraction’

+ milk let-down

Question 10

What causes milk production/initiation

lactogenesis

Answer 10

• progesterone
• pregnancy
• Colostrum

Question 11

what biochemical factors causes secretory activation

Answer 11

• low progesterone/oestrogen
• high prolactin (cortisol,insulin)
• copious milk production after delivery
• —-2-3 days post-partum

Question 12

what are the effects of prolactin on GnRH, LH FSH and oestrogen/testosterone

Answer 12

decreases all of them

Question 13

what is the presentation of hyperprolactinaemia

Answer 13

Men-

• usually have visual symptoms
• don’t produce milk
• have erectile dysfunction
• decreased libido

women-

• amenorrhoea
• galactorrhoea
• present after stopping the pill

Question 14

difference between micro and macro

Answer 14

cm bounds

Question 15

what are the causes of hyperprolactinaemia

Answer 15

Physiological- preg and lactation

Drugs

Polycystic ovarian syndrome

Hypothalamic-pituitary disease- icro/macroPRLoma
& non-functioning adenoma

Question 16

what drugs can increase prolactinaemia

Answer 16

-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

Question 17

what investigations can you do

Answer 17

• pregnancy test
• renal function
• liver function tests

Question 18

what are the aims of treatment

Answer 18

• Restore fertility
• stop galactorrhoea
• Restore menstrual periods
• Shrink tumour

Question 19

How do you manage a PRLoma

Answer 19

MEDICAL’​
Dopaminergic drugs​
-Cabergoline​
-(Bromocriptine)​

Preserve pituitary function​

Side-effects​
-RARE:​
--Fibrotic reactions​
-Pulmonary, --pericardial, retroperitoneal​
--Psychiatric disturbances ​
​

Question 20

PRLoma management for MicroPRlomas

&

Idiopathic hyperPRLaemia

Answer 20

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​

Question 21

NFA (pituitary adenoma) management

Answer 21

Surgery & radiotherapy

risks loss of pituitary function

Question 22

Look at cases and use this info to do quiz

Answer 22

How did it go?