Flashcards in Session 5 - Sex Steroid Hormones Deck (28)
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1
What are sex steroids synthesised from?
Cholesterol
2
What are the actions of oestrogen?
Mild anabolic
Sodium and water retention
Raises HDL, lowers LDL
Decreases bone resorption
Impairs glucose tolerance
Increases blood coagulability
3
What are the side effects of taking oestrogen?
Breast tenderness
Nausea and vomiting
Water retention
Increased blood coagulability
Thromboembolism
Impaired glucose tolerance
Endometrial hyperplasia and cancer
Ovarian metaplasia and cancer
Breast hyperplasia and cancer
4
What are the actions of progesterone/progestin?
Anabolic
Secretory endometrium
Increase bone mineral density
Fluid retention
Mood changes
Maintains pregnancy
5
What are the side effects of taking progesterone/progestin?
Weight gain
Fluid retention
Acne
Nausea/vomiting
Irritability
Depression
Premenstrual syndrome
Lack of concentration
6
What are the side effects of taking testosterone?
Male secondary sex characteristics
Acne
Voice changes
Increased aggression
Increased risk of atherosclerotic disease (affects HDL-C/LDL-C ratio)
7
Give examples of synthetic derivatives of oestrogen.
Ethinylestradiol
Valerate
8
Give examples of synthetic derivatives of progesterone.
Medroxyprogesterone
Dydrogesterone
9
How are sex steroid hormones transported in the blood?
Transported bound to sex hormone binding globule (SHBG) (except progesterone) and to albumin.
10
Why are sex steroids easily stored in fatty tissue?
They are lipophilic, they complex into the plasma membrane in the same way as cholesterol.
11
Sex steroid hormones bind to what kind of receptors?
Nuclear receptors
12
What are the types of nuclear receptors for each of the sex steroid hormones?
Oestrogen:
ERa and ERb
Progesterone:
PR-A and PR-B
Androgens:
AR-1 and AR-2
13
What are the two types of oral contraceptive pill?
Combined oral contraceptive pill (COCP) - oestrogen and progestin
Progestin only pill (POP)
14
What is the mechanism of action of the combined oral contraceptive pill (COCP)?
Suppression of ovulation - it inhibits FSH and LH release.
Increases viscosity of cervical mucus.
Prevent the endometrium from entering the secretory phase.
15
What are the ADRs of the COCP?
Venous thromboembolism
Myocardial infarction
Hypertension
Decreased glucose tolerance
Increased risk of stroke in women with focal migraine
Headaches
Mood swings
Cholestatic jaundice
Increased incidence of gallstones
Precipitates porphyria
16
Where is the COCP metabolised?
In the liver by cytochrome p450
17
What drug interactions reduce the efficacy of the COCP?
COCP efficacy reduced by cytochrome p450 inducing drugs, such as:
- antiepileptics - carbamazepine, phenytoin
- some antibiotics - rifampicin, rifabutin
- some natural products - St John’s wort
18
Give examples of emergency contraceptives.
Up to 72 hours post sex:
- levonorgestrel (Levonelle)
Up to 120 hours post sex:
- ullipristal acetate (EllaOne) - selective progesterone receptor modulator
- Cu2+ IUD - prevents blastocyst attachment to endometrium
19
What are the benefits of postmenopausal hormone replacement therapy (HRT)?
Reduces menopausal symptoms: hot flushes, sweats, vaginal dryness, dyspareunia
Reduces risk of osteoporosis
20
What are the risks and ADRs of HRT?
Unopposed oestrogen (ERT) - increased risk of developing endometrial and ovarian cancers
Opposed oestrogen (HRT) - increased risk of developing breast cancer
Increased risk of stroke and ischaemic heart disease
Increased risk of thromboembolism
21
Explain the mechanism of action of Clomiphene.
Clomiphene: ovulation induction
Clomiphene inhibits the binding of oestrogen to its ER in the anterior pituitary. This inhibits the negative feedback on the anterior pituitary and therefore increases the production of LH and FSH.
22
Explain the mechanism of action of Tamoxifen.
Tamoxifen: reduces risk of breast cancer.
Tamoxifen binds to the oestrogen receptor in breast tissue and therefore stops the oestrogen-stimulated myoepithelial cell division.
Also causes ovulation induction.
23
Give an examples of an anti-progestin.
Mifepristone
24
What is the function of Mifepristone?
Sensitises the uterus to prostaglandins.
Used for medical termination of pregnancy and induction of labour.
25
Give an example of an anti-androgen.
Cyproterone
26
Give an example of a Selective Oestrogen Receptor Modulator (SERM).
Raloxifene
27
What is the function of Raloxifene?
Protects against osteoporosis. Oestrigenic effects on bone, lipid metabolism and blood coagulation. No proliferative effects on endometrium and breast.
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