4.1 Sex Steroid Hormones Flashcards
How is oestrogen transported in the blood?
Bound to SHBG (sex hormone binding globulin)
Why is oestrogen binding to SHBG important?
Protects it from hepatic metabolism
Allows oestrogen to be stored in fatty tissue and the brain
Why is progesterone almost completely metabolised in first pass metabolism?
Not bound to SHBG- in free form
Name the 3 main sex hormones
Oestradiol
Progesterone
Testosterone
How does the Combined Oral Contraceptive Pill work?
Inhibits LH and FSH so ovulation is suppressed. It makes the cervical mucous more viscous and prevents the secretory phase of the endometrium
List some common ADRs of the COCP
Weight gain
Hypertension
Headaches
Increased risk of MI, stroke and thromboembolism
What drugs can lower the effectiveness of the COCP?
Carbamazepine
Rifampicin
St. John’s Wart
Who is treated with hormone replacement therapy?
Post-menopausal women with hot flushes and vaginal dryness
When taking unopposed oestrogen, what is the patient more at risk of?
Endometrial and ovarian cancers
When taking opposed oestrogen, what is the patient more at risk of?
Breast cancer
What do HRTs increase the risk of other than cancers?
Thromboembolism
Stroke
What is the mechanism of action of Clomiphene?
Oestrogen antagonist in the pituitary
Pituitary thinks the body’s oestrogen is low so releases more LH/FSH. This induces ovulation
What is the function of Tamoxifen?
Induces ovulation
Blocks oestrogen
What is the drug Mifepristone used for?
Medical termination of pregnancy
What drug is used as the ‘morning-after’ pill?
Levonorgestrel
