Lactation, Galactorrhoea, Prolactinomas

Question 1

What is lactation?

Answer 1

• process of making breast milk

- process of secretion of milk by mammary glands

Question 2

Where does the name galactorrhoea originate?

Answer 2

• galacto = greek for milk

- rheo = greek for flow

Question 3

The name galactorrhoea originates from greek:

• galacto = greek for milk
• rheo = greek for flow

What does galactorrhoea mean?

Answer 3

• milky nipple discharge

- not related to normal milk production of breast-feeding

Question 4

Label the image below using the labels here:

pectoralis major
areola
nipple
adipose tissue
lactiferous duct
lobules and alveoli
lactiferous sinus (ampulla)

Answer 4

1 = pectoralis major
2 = adipose tissue
3 = lobules and alveoli
4 = lactiferous sinus (ampulla)
5 = lactiferous duct
6 = nipple
7 = Areola

Question 5

The lobules of the breast are adapted sweat glands that secrete milk and are composed of multiple alveoli. Using the labels below, label one of the alveoli in the image below using the provided labels:

• milk
• ductule
• milk secreting epithelial cells
• myoepithelial cells

Answer 5

1 - myoepithelial cells
2 - milk
3 - milk secreting epithelial cells
4 - ductule

Question 6

Once the milk is produced by the epithelial cells of the alveoli, what is the flow form the alveoli to the nipples?

1 - epithelial cells, ductule, lactiferous sinus, lactiferous duct, nipple
2 - epithelial cells, lactiferous sinus, ductule, lactiferous duct, nipple
3 - epithelial cells, ductule, lactiferous duct, lactiferous sinus, nipple
4 - epithelial cells, lactiferous sinus, lactiferous duct, ductule, nipple

Answer 6

3 - epithelial cells, ductule, lactiferous duct, lactiferous sinus, nipple

Question 7

In puberty there are 3 hormones that contribute to the development of breast tissue, specifically the alveolar and lobules, what are these 3 hormones?

Answer 7

1 - progesterone
2 - estrogen
3 - growth hormone

Question 8

In puberty there are 3 hormones that contribute to the development of breast tissue, specifically the alveolar and lobules:

1 - progesterone
2 - estrogen
3 - growth hormone

What growth factor does growth hormone act through?

Answer 8

• insulin growth factor-1 (IGF-1)

Question 9

In pregnancy there are 4 hormones that contribute to the development of breast tissue, specifically the alveolar and lobules, what are these 3 hormones?

Answer 9

1 = oestrogen
2 = progesterone
3 = human chorionic gonadotrophin
4 = prolactin

First 3 are all produced by placenta, so when the placenta is delivered prolactin is dominant

Question 10

The image below shows histology tissue from 4 different time points for woman’s breast development. Label the image using the labels below to identify each time period:

pregnancy
virgin
involution
lactation

Answer 10

1 - virgin
2 - pregnancy (increased alveoli and lobules)
3 - lactation
4 - involution

Question 11

Following breast feeding, breast tissue is said to involute, what does this mean?

Answer 11

• shrinking or return to normal size of an organ

- alveoli and lobular number reduce

Question 12

In pregnancy there are 4 hormones that contribute to the development of breast tissue, specifically the alveolar and lobules:

1 = oestrogen
2 = progesterone
3 = human chorionic somatomammotropin
4 = prolactin

Although this prepares the breasts for milk synthesis and secretion, during pregnancy they don’t normally secrete milk. High levels of one of these hormones produced by the placenta inhibit milk let down. Which hormone is responsible for this inhibition?

Answer 12

• progesterone

Question 13

Once a baby is born and the placenta has been delivered the placenta based progesterone levels drop, allowing milk to flow. However, milk is not the first thing that is secreted. What is secreted?

Answer 13

• colostrum

- high in protein, carbs, immune cells (IgA) and low in fat

Question 14

Once a baby is born and the placenta has been delivered the placenta based progesterone levels drop, allowing milk to flow. However, the first thing secreted is colostrum, which is high in protein, immune cells and low in fat, In addition to nourishing the baby, what does colostrum do to the GIT?

Answer 14

• acts as a laxative

- helps baby pass the first poo called meconium

Question 15

What is prolactin and where is it synthesised and secreted?

Answer 15

• hormone produced by anterior pituitary gland

- produced by lactotrophs cells

Question 16

Prolactin is a hormone synthesised and secreted by the anterior pituitary gland, produced by lactotrophs cells. What is the function of prolactin?

Answer 16

• stimulates breast tissue to synthesise and secrete breast milk

Question 17

What is oxytocin and where is it synthesised and secreted?

Answer 17

• peptide hormone synthesised and secreted by posterior pituitary gland

Question 18

Oxytocin is a peptide hormone synthesised and secreted by posterior pituitary gland. Oxytocin has 2 key functions, what are they?

Answer 18

1 - signals myoepithelial cells of breast glands to contract and secrete milk
2 - part of positive feedback loop to trigger uterus contractions in labour

Question 19

In pregnancy there are 4 hormones that contribute to the development of breast tissue, specifically the alveolar and lobules:

1 = oestrogen
2 = progesterone
3 = human chorionic somatomammotropin
4 = prolactin

What is the role of estrogen and progesterone on the breasts during pregnancy?

Answer 19

• physical development of the breast

- inhibition of breast milk secretion (mainly progesterone)

Question 20

In the first 1-7 days following birth the breast secrete copious amounts of milk after colostrum. What hormones are important in the the secretion of this breast milk, ensuring adequate supply of amino acids, fatty acids, glucose, and calcium?

1 - growth hormone, parathyroid hormone,insulin, estrogen
2 - growth hormone, cortisol, parathyroid hormone,andestrogen
3 - growth hormone, cortisol, parathyroid hormone,andinsulin
4 - growth hormone, FSH, parathyroid hormone,andinsulin

Answer 20

3 - growth hormone, cortisol, parathyroid hormone,andinsulin

Question 21

Following birth and the delivery of the placenta there is a substantial drop in estrogen and progesterone. Which then results in an increase in what key hormone secreted by the anterior pituitary gland?

Answer 21

• prolactin

Question 22

Following birth and the delivery of the placenta there is a substantial drop in estrogen and progesterone. Which then results in an increase in prolactin secreted by the anterior pituitary gland. What normal response can cause a positive feedback loop to stimulate further secretion of prolactin and therefore more breast milk synthesis and secretion?

Answer 22

• breastfeeding
• suckling provides tactile stimulation to hypothalamus
• hypothalamus responds with increased prolactin

Question 23

Following birth and the delivery of the placenta there is a substantial drop in estrogen and progesterone. Which then results in an increase in prolactin secreted by the anterior pituitary gland, which can be further increased through breastfeeding. Prolactin also has an inhibitory effect on the hypothalamus causing the reduction in the secretion of what 3 hormones that are involved in the menstrual cycle?

Answer 23

1 - gonadotrophin releasing hormone (GnRH) inhibited from hypothalamus
2 - no GnRH means no LH and FSH secreted from pituitary gland

Question 24

Prolactin increases following birth to synthesise and secrete breast milk. This results in inhibition of:

1 - gonadotrophin releasing hormone (GnRH) inhibited
2 - no GnRH means no LH and FSH

What effect does this have on the ovaries and the menstrual cycle?

Answer 24

• no follicular development and maturation
• no ovulation, so generally no periods when breast feeding
• 100% breast feeding is a form of contraception

Question 25

In a woman who is not pregnant, the release of prolactin is inhibited. What causes this inhibition?

Answer 25

- dopamine also called prolactin inhibiting factor | - secreted by the hypothalamus

Question 26

In a woman who is not pregnant, the release of prolactin is inhibited by dopamine also called prolactin inhibiting factor. This is secreted by what cell nucleus in the hypothalamus?

Answer 26

- arcuate nucleus

Question 27

In a woman who is not pregnant, the release of prolactin is inhibited by dopamine also called prolactin inhibiting factor. This is secreted by the arcuate nucleus in the hypothalamus. In addition to inhibiting prolactin, what other hormone is dopamine able to inhibit the release of from the hypothalamus?

Answer 27

- thyrotropin-releasing hormone

Question 28

What is the process called milk let down, also known as milk ejection?

Answer 28

- suckling triggers hypothalamus - pituitary releases prolactin and oxytocin - breasts fill up (prolactin) and myoepithelial cells contract (oxytocin) - baby suckles on breasts causes the secretion of breast milk from the breast

Question 29

The figure below shows the levels of 3 key hormones following parturition (time following birth). Use the labels below to label the 3 key hormones: - progesterone - estrogen - prolactin

Answer 29

1 - estrogen 2 - progesterone 3 - prolactin (goes up and down during breastfeeding)

Question 30

What 2 key sugars are present in breast milk? 1 - lactose and oligosaccharides 2 - glucose and lactose 3 - disaccharides and lactose 4 - lactose and disaccharides

Answer 30

1 - lactose and oligosaccharides

Question 31

What 3 hormones triggers the release of prolactin from the anterior pituitary gland?

Answer 31

1 - 5HT (serotonin) 2 - TRH (Thyrotropin releasing hormone) 3 - OXT (oxytocin)

Question 32

Galactorrhoea refers to milky nipple discharge that is not related to normal milk production of breast-feeding. High levels of which hormone as associated with galactorrhoea?

Answer 32

- prolactin, also called hyperprolactinaemia

Question 33

High levels of prolactin called hyperprolactinaemia is a common cause of galactorrhea. What are the 4 key presentations that are common in women who have hyperprolactinaemia?

Answer 33

1 - amenorrhoea (absence of bleeding) 2 - galactorrhea (non-pregnancy related milky discharge) 3 - subfertility (low levels of LH and FSH due to low GnRH) 4 - hypopituitarism

Question 34

High levels of prolactin called hyperprolactinaemia is a common cause of galactorrhea. What are the 5 key presentations that are common in men who have hyperprolactinaemia?

Answer 34

- reduced libido - visual symptoms - headaches - hypopituitarism - gynaecomastia

Question 35

Prolactin increases following birth to synthesise and secrete breast milk. This results in inhibition of: 1 - gonadotrophin releasing hormone (GnRH) inhibited 2 - no GnRH means no LH and FSH (reducing estrogen production) This causes no follicular development and maturation or no ovulation, so generally no periods when breast feeding. In a patient with hyperprolactinaemia, this may further decrease levels estrogen which can have what affect on the bones of women?

Answer 35

- estrogen maintains osteoblast and osteoclast balance - low estrogen = high osteoclasts (dissolve bone) - increases risk of fracture and osteoporosis

Question 36

What affect can hyperprolactinaemia have on the testes?

Answer 36

- increased prolactin inhibits GnRH - low GnRH = low testosterone - low testosterone = reduced spermatogenesis

Question 37

Hyperprolactinaemia can be causes by a pituitary tumour. What effect can this have on the eyes?

Answer 37

- tumour may press on the optic chiasm | - causes bitemporal hemianopia and press on meninges causing pain

Question 38

Hyperprolactinaemia can commonly be caused by what 2 physiological processes?

Answer 38

1 - pregnancy (continued milk production for up to 2 years) | 2 - parturition (giving birth)

Question 39

Hyperprolactinaemia can commonly be caused by what 2 hypothalamic pituitary disease?

Answer 39

1 - micro / macroPRLoma (varying size of tumour on pituitary gland 2 - non-functioning adenoma

Question 40

Hyperprolactinaemia can commonly be caused by what 2 day to day activities?

Answer 40

1 - adverse events of drugs | 2 - stress

Question 41

Hyperprolactinaemia can commonly be caused by hypothyroidism, why?

Answer 41

- low secretion of thyroid hormones means no negative feedback loop - hypothalamus increases secretion of thyrotropin releasing hormone - thyrotropin releasing hormone stimulates release of prolactin

Question 42

What is a prolactinoma?

Answer 42

- hormone on pituitary gland | - causes excessive levels of prolactin to be released

Question 43

In Addisons disease, which is essentially hypoadrenalism, there is low levels of cortisol. How can this lead to hyperprolactinaemia?

Answer 43

- high cortisol inhibits the release of prolactin | - low cortisol = high prolactin

Question 44

Antidepressants, antipsychotics and drugs used for nausea & vertigo (Phenothiazines, Metoclopramide and Domperidone) can also cause Hyperprolactinaemia. How does this occur?

Answer 44

- act as dopamine antagonists = increased prolactin release | - acts as serotonin activators = increased prolactin

Question 45

What blood tests can be performed in an attempt to identify the cause of hyperprolactinaemia?

Answer 45

- pregnancy test - renal function (U&E, creatinine) - liver function tests - thyroid function - prolactin levels - hormones (LH, FSH, GH, IGF1, oestradiol and testosterone)

Question 46

Why would an MRI be useful in an attempt to identify the cause of hyperprolactinaemia?

Answer 46

- identify if a tumour is present on pituitary gland

Question 47

What are the 4 key aims when treating hyperprolactinaemia?

Answer 47

- restore fertility (MAIN AIM) - stop galactorrhea - restore regular cycles and libido (reduce osteoporosis) - shrink tumour

Question 48

A pituitary adenoma can be divided into: - Functional adenoma or prolactinoma - Non functional adenoma (NFA) What is a functional adenoma or prolactinoma?

Answer 48

- when a tumour causes excess production of one or more hormones - prolactinoma is an example where a tumour causes overproduces of prolactin - acromegaly (adults), gigantism (child), causes an excess growth hormone secretion

Question 49

What is the medical treatment for prolactinoma?

Answer 49

- dopaminergic drugs = Cabergoline and Bromocriptine | - same effects as dopamine so able to inhibit prolactin

Question 50

What is a nonfunctioning pituitary adenoma?

Answer 50

- a benign growth in the pituitary gland that does not produce any excessive hormone into the blood and is not cancerous

Question 51

A nonfunctioning pituitary adenoma is a benign growth in the pituitary gland that does not produce any excessive hormone into the blood and is not cancerous. How is this treated?

Answer 51

- surgery and radiotherapy | - patient could lose pituitary function during surgery