Reproductive Endocrinology

Question 1

Subtype of hormones?

Answer 1

• Proteins and peptide hormones e.g. insulin
• Steroid hormones e.g. testosterone, oestrogen, progesterone
• Amino acid derived hormones e.g. adrenaline, thyroxine, melatonin

Question 2

Types of hormone receptors?

Answer 2

• G-protein coupled receptors
• Receptor tyrosine kinase
• Receptors associated with tyrosine kinase activity
• Steroid hormone receptors

Question 3

How do steroid hormone receptors work?

Answer 3

Hormone binds to receptor –> steroid/receptor complex binds to DNA response elements –> change in gene transcription

Question 4

What is the hypothalamic pituitary gonadal axis?

Answer 4

Hypothalamus produces GnRH which stimulates the anterior pituitary to produce LH and FSH

LH and FSH act on the testes and ovaries to produce oestrogen, testosterone and progesterone

Negative or positive feedback loop to the ant. pituitary and hypothalamus

Question 5

What stimulates GnRH secretion?

Answer 5

Kisspeptin

Question 6

Describe prolactin secretion?

Answer 6

Prolactin is secreted from the anterior pituitary and is under tonic inhibition from hypothalamic dopamine

Question 7

Prolactin is responsible for…

Answer 7

breast development and lactation

Question 8

Possible causes of high prolactin?

Answer 8

Prolactinoma
Pituitary tumours
Drugs e.g. antipsychotics and dopamine agonists

Question 9

Overview of steroid hormone synthesis?

Answer 9

LH binds to Leydig and Theca cells which increases expression of StAR which promotes cholesterol transfer to the inner mitochondrial membrane and initiates steroidogenesis

Cholesterol converted to pregnenolone which is then converted to oestrogen, progesterone or testosterone

Question 10

Where is testosterone produced?

Answer 10

Leydig cells in the testes

Question 11

What converts testosterone to dihydrotestosterone?

Answer 11

5-alpha reductase

Question 12

What is the most biologically active form of testosterone in the body?

Answer 12

Dihydrotestosterone

Question 13

Where is oestrogen produced?

Answer 13

Granulosa and Theca cells of ovaries
Corpus luteum

Question 14

Where is progesterone produced?

Answer 14

Corpus luteum
Placenta in pregnancy
Adrenal gland

Question 15

What is oligoamenorrhoea?

Answer 15

reduction in frequency of periods to <9 per year

Question 16

What is primary amenorrhoea?

Answer 16

failure of menarche by 16 years

Question 17

What is secondary amenorrhoea?

Answer 17

cessation of periods for >6 months in an individual who has previously menstruated

Question 18

Causes of amenorrhoea?

Answer 18

Physiological - pregnancy, menopause

Primary - congenital problems e.g. Turners, Kallmann

Secondary - PCOS, POF, adhesions, weight loss, exercise, stress, high prolactin

Question 19

Investigations for amenorrhoea?

Answer 19

LH, FSH, oestradiol, thyroid function, prolactin

US
Testosterone
Pituitary function tests + MRI
Karyotyping

Question 20

Levels of FSH, LH and oestrogen in primary hypogonadism?

Answer 20

Problem with the ovaries
- high LH and FSH
- low oestrogen

Question 21

Levels of FSH, LH and oestrogen in secondary hypogonadism?

Answer 21

Problem with hypothalamus or pituitary
- low LH and FSH
- low oestrogen

Question 22

What is Premature Ovarian Failure?

Answer 22

Amenorrhoea, oestrogen deficiency and high FSH/LH occurring <40 years old as a result of loss of ovarian function

Question 23

Possible causes of premature ovarian failure?

Answer 23

Chromosome abnormalities e.g. Turner’s syndrome, Fragile X syndrome

Gene mutations

Autoimmune e.g. Addison’s, thyroid

Iatrogenic - radiotherapy, chemotherapy

Question 24

What can cause functional hypothalamic amenorrhoea?

Answer 24

Weight loss
Stress
Excessive exercise

Question 25

What are the diagnostic criteria for PCOS?

Answer 25

• Menstrual irregularity
• Hyperandrogenism - hirsutism, acne, alopecia, high testosterone
• Polycystic ovaries on US

Question 26

What is Turner’s syndrome?

Answer 26

XO karyotype

Question 27

Congenital causes of primary hypogonadism in males?

Answer 27

Klinefelter’s syndrome

Question 28

Acquired causes of primary hypogonadism in males?

Answer 28

Testicular trauma
Radiotherapy and chemotherapy
Varicocele

Question 29

What is Klinefelter’s syndrome?

Answer 29

XXY - presence of an extra X chromosome in men

Question 30

Testosterone, FSH and LH levels in primary hypogonadism?

Answer 30

low testosterone
high LH and FSH

Question 31

Testosterone, FSH and LH levels in secondary hypogonadism?

Answer 31

low testosterone
low LH and FSH