S5.2 Sex Steroid Hormones

Question 1

What are the effects of oestrogen?

Answer 1

Stimulates growth of the endometrium and breast

Question 2

What are the actions and ADRs of oestrogen?

Answer 2

Na and water retention, decrease bone resorption

ADRs: breast tenderness, nausea

Question 3

What are the effects of progesterone?

Answer 3

Stimulates growth of the endometrium and breast; maintains pregnancy and prepares endometrium for implantation

Question 4

What are the actions and ADRs of progesterone?

Answer 4

Increases bone density

ADRs: weight gain, acne

Question 5

What are the effects of testosterone?

Answer 5

Stimulates male characteristics e.g pubes, deep voice

Question 6

What are the ADRs of testosterone?

Answer 6

Acne, aggression

Question 7

Describe the transport of sex steroid hormones

Answer 7

Transport bound to SHBG (sex hormone binding globule, production upregulated by oestrogen) and albumin

Question 8

Describe the pharmacokinetics of sex steroid hormones

Answer 8

Liver metabolism: hormones metabolised in one passage through liver.
Stored in fatty tissue which increases half life

Question 9

What is the mechanism of the OCP?

Answer 9

Oestrogen (ethinyloestradiol) + progesterone (levonorgestrel).
Prevents ovulation (inhibits FSH LH), thickening of cervical mucous

Question 10

What are the ADRs of the OCP?

Answer 10

Venous thromboembolism, MI, Hypertension.
Metabolised by CP450, so there efficacy is reduced by enzyme inducing drugs;
Phenytoin, Carbamazapine, Rifampicin, Rifabutin (as all increase CP450)

Question 11

Describe the features of the progesterone-only pill

Answer 11

E.g: levonorgestrel, norethisterone, medroxyprogesterone.
Thickens cervical mucus so impenetrable to sperm.
ADRs: menstrual problems common

Question 12

What advice would you give to a woman who missed the pill on one day?

Answer 12

Take last pill immediately and continue others as normal. May need extra contraception for next 7 days.

Question 13

What are the two forms of emergency contraception?

Answer 13

Levonorgestrel (72h after sex), ulipristal acetate (120h after sex).

Question 14

Describe the two types of HRT

Answer 14

Unopposed oestrogen (E)RT - risk of endometrial or ovarian cancer. 
Opposed oestrogen (H)RT - risk of breast cancer.
Both reduce menopausal symptoms, and can increase HDL

Question 15

What is the mechanism of clomiphene?

Answer 15

Ovulation induction: inhibits oestrogen to its receptor in the anterior pituitary, inhibits negative feedback, so results in increased FSH, LH expression

Question 16

What is the mechanism of tamoxifen?

Answer 16

Reduces risk of breast cancer: Binds to oestrogen receptor in breast tissue and blocks oestrogen-stimulated myoepithelial cell division

Question 17

What is the mechanism of anti-progestins (mifepristone)?

Answer 17

Inhibits progesterone action.

Sensitises the uterus to prostaglandins, is used for termination of pregnancy and induction of labour

Question 18

What is the mechanism of anti-androgens (cyproterone)?

Answer 18

Partial agonist at progesterone receptor, that competes with DHT. Used to treat prostate cancer.

Question 19

What is the mechanism of the SERM raloxifene?

Answer 19

Protects against osteoporosis.

Reduced risk of invasive breast cancer in postmenopausal women with osteoporosis