7 - Sex Hormones Flashcards
What are the major effects of oestradiol, progesterone and testosterone??
What are three groups of drugs when considering sex hormones?
Why do drugs based on sex hormones take a while for a response?
They are steroid hormones so act through nuclear receptors so longer response
What are the actions and side effects of oestrogen?
What are the actions and side effects of progesterone?
What are the actions and side effects of testosterone?
What are the different routes of administration for sex steroid hormones?
- Oral
- Transdermal patch
- Implants
- Nasal
- Vagina
How are sex steroids transported in the blood?
- Transport bound to SHBG (except progesterone) and albumin
- SHBG production upregulated by oestrogens – protects against hepatic metabolism
What are some side effects of the combined pill?
- Thromboembolic disease (higher in obese, hypertensives, smokers, long term users and over 35)
- Mood swings
- Decreased glucose tolerance
- Mood swings
- Hypertension
How are sex hormone drugs metabolised and excreted?
- CYP450 in liver
- Metabolites are excreted in faeces and urine as glucuronides and sulphates, respectively
What is the mechanism of action for the COCP and POP?
COCP:
- Suppression of ovulation (inhibits FSH, LH)
- Thickens cervical mucus (more viscous)
- Prevents secretory phase in endometrium (remains atrophic)
POP: (low dose)
- Thicken cervical mucous
- Atrophy endometrium
- High dose implant stops ovulation but this doesn’t
- Need constant oestrogen as progestrone receptors only present when oestrogen around so not good if woman producing low oestrogen
What are some side effects of POP?
In the COCP, which progestins are prescribed?
- Medroxyprogesterone acetate
- Norethisterone
- Levonorgesterel
In the COCP, which oestrogens are prescribed?
ethinylestradiol
How are sex hormones synthesised?
From cholesterol
Why is HRT prescribed?
- Helps the symptoms of menopause e.g hot flushes, dyspareunia, genital atrophy
- Helps osteoporosis
- NOT cardioprotective
Identify five types of steroids used in HRT and their dosing regimen
- Oestrogen only: can only be given to a woman without a uterus
- HRT: progesterone given with oestrogen as progesterone has antiproliferative effects on endometrium
What are the side effects/risks of HRT?
- Increased chance of breast cancer (mainly HRT)
- Increased risk of endometrial and ovarian cancer in unopposed oestrogen
- Risks of DVT and PE as oestrogen makes you hypercoagulable (only oral)
- Stroke and ischaemic heart disease
What is the mechanism of action of Mifepristone (RU486) and what class of drug is it?
- Antiprogesterone: Progesterone and glucocorticoid antagonist
- Sensitises the myometrium to prostaglandin induced contraction
- Terminates pregnancy or labour induction
What class of drug is clomiphene and what is it used for?
- SERM: selective oestrogen receptor modulator
- Varying effects depending what tissue it is in
- Induces ovulation as prevents oestrogen binding to receptor on anterior pituitary and having negative feedback so increased FSH and LH
What class of drug is Tamoxifen and what is it used for?
- SERM
- Prodrug metabolised in the liver to become active
- Reduces breast cancer (or risk of) in ER positive cases as binds ER antagonist so binds to ER stopping myoepithelial growth
- In endometrium it acts as ER agonist so can cause menopausal side effects and endometrial cancer
What are two emergency contraceptives and what are their mechanisms of action?
- Levonorgestrel (up to 72 hours): progestogen. stops ovulation and/or prevents sperm fetilising an egg
- Ulipristal Acetate (up to 120 hours): selective progesterone receptor modulator. delays or inhibits ovulation and can be used to treat uterine fibroids
What can SERMs be used for?
- Breast cancer chemotherapy
- Anovulation
- HRT
