7) Sex Steroid Hormones

Question 1

What is the function of GnRH?

Answer 1

Stimulates synthesis and secretion of LH and FSH

Question 2

What is the function of FSH?

Answer 2

Follicle growth and oocyte maturation

Question 3

What is the function of LH?

Answer 3

Ovulation and causes ruptured follicle to become corpus luteum

Question 4

What is the function of oestrogen in the menstrual cycle?

Answer 4

Repair and growth of endometrium

Question 5

What is the function of progesterone in the menstrual cycle?

Answer 5

Preparation of endometrium for implantation and promotes growth of mammary glands

Question 6

How are the sex steroids transported?

Answer 6

Bound to sex hormone binding globulins (except progesterone) and albumin

Question 7

What regulates sex hormone binding globulins?

Answer 7

Production upregulated by oestrogen

Question 8

How can the sex steroids be stored?

Answer 8

In fatty tissue (adipocytes and brain), complex into plasma membrane

Question 9

How are the sex steroids excreted?

Answer 9

Metabolites excreted in faeces and urine as glucuronides and sulphates

Question 10

Describe the enterohepatic recirculation of oestrogen:

Answer 10

Oestrogen conjugated with glucuronide and into bile. Intestinal bacteria unconjugate oestrogen so it gets recycled into blood

Question 11

How is sex steroid hormone binding to nuclear receptors regulated?

Answer 11

Co-factors stabilise the hormone-receptor complex

Integrators have the opposite effect

Question 12

Describe the isoforms of steroid hormone receptors:

Answer 12

Oestrogen: ER alpha, ER beta
Progesterone: PR-A and PR-B
Androgen: AR1 and AR2

Question 13

What are the 3 sex steroid hormones and their effects?

Answer 13

Oestradiol - stimulates growth of endometrium, breast and production of PR
Progesterone - maintains pregnancy, growth of endometrium and breast, inhibits production of ER
Testosterone - simulates male characteristics, anabolism, aggression

Question 14

How are the sex steroids synthesised?

Answer 14

Synthesised from cholesterol
Oestradiol formation occurs in adrenal, adipose and gonads
Progesterone and testosterone in gonads

Question 15

What molecule can be used as a pregnancy marker?

Answer 15

Estriol

Question 16

What are the side effects of too much oestrogen?

Answer 16

Breast tenderness
Water retention (bloating)
Thromboembolism
Breast, ovary and endometrial hyperplasia + cancer

Question 17

What are the side effects of too much progesterone?

Answer 17

Weight gain 
Acne
Irritability
Depression
PMS

Question 18

What are the side effects of too much testosterone?

Answer 18

Adverse effects on lipid profile to increased risk of atherosclerosis

Question 19

What are the types of COCP?

Answer 19

Monophasic - fixed oestrogen and progestin
Biphasic - oestrogen constant, progestin increases second half
Triphasic - oestrogen for first 14, progestin 1-7 and 14-21

Question 20

Describe the COCP:

Answer 20

Synthetic oestrogens and 1st to 4th generation progesterone

Question 21

How can the COCP be administered?

Answer 21

Oral, transdermal patch, implants

Question 22

What is the mechanism of action of the COCP?

Answer 22

Inhibits FSH and LH to prevent ovulation, also thickens cervical mucus and keeps endometrium atrophic

Question 23

What are the adverse effects of the COCP?

Answer 23

Venous thromboembolism
MI and HTN
Gallstones (increased cholesterol to liver)

Question 24

What potential drug interactions can occur with the COCP?

Answer 24

Inducers: rifampicin, carbamazepine, phenytoin, St John’s Wort

Question 25

What should be monitored when on the COCP?

Answer 25

BP, BMI, side effects

Question 26

Describe the POP:

Answer 26

28 days of progestin

Question 27

What can be used as emergency contraception up to 72 hours post coitus?

Answer 27

Levonorgestrel

Question 28

What can be used as emergency contraception up to 120 hours post coitus?

Answer 28

Ullipristal acetate - selective progesterone receptor modulator Copper IUD

Question 29

When is hormone replacement therapy prescribed?

Answer 29

For hot flushes and vaginal dryness (symptoms of menopause)

Question 30

When is HRT contraindicated?

Answer 30

Heart disease

Question 31

What is the difference between ERT and HRT?

Answer 31

ERT - oestrogen replacement therapy | HRT - hormone (progesterone and oestrogen) replacement therapy

Question 32

What are the risks of ERT?

Answer 32

Increased risk or endometrial and ovarian cancer

Question 33

What are the risks of HRT?

Answer 33

Increased risk of breast cancer | Risk of stroke, risk of VTE

Question 34

What are the routes of administration for HRT?

Answer 34

Oral, transdermal, implant, transvaginal, nasal

Question 35

What is the mechanism of action of clomiphene and what is it used for?

Answer 35

Inhibits oestrogen by binding to ER in anterior pituitary causing decreased negative feedback and increased FSH and LH Used for ovulation induction in IVF

Question 36

What is the mechanism of action of tamoxifen and what is it used for?

Answer 36

Binds to ER in breast and blocks oestrogen stimulated myoepithelial cell division Decreases risk of breast cancer

Question 37

What is the mechanism of action of mifepristone and what is it used for?

Answer 37

Partial agonist at PR and sensitises uterus to prostaglandins Used for medical termination of pregnancy or induction of labour

Question 38

Describe an androgen replacement therapy and its use:

Answer 38

Finasteride blocks 5-alpha reductase from catalysing testosterone -> 5DHT Prevents hair loss and BPH