Flashcards in Session 4 Deck (40):
What are the sex hormones derived from?
How do oestrogens work?
Dissociate from sex-hormone binding globulin in the plasma, diffuse across the cell membrane and bind to specific nuclear receptor proteins. This then activates nuclear chromatin to initiate hormone-specific RNA synthesis.
What is the role of oestrogen in the menstrual cycle?
Inhibits secretion of FSH, hence suppresses development of the ovarian follicle.
What is the role of progesterone in the menstrual cycle?
Inhibits secretion of LH, hence prevents ovulation. Also makes cervical mucus less suitable to the passage of sperm.
What is the role of progesterone secreted by the corpus luteum?
-Continues preparation of endometrium for a pregnancy
-Inhibits contraction of the uterus
-Inhibits development of a new follicle.
What happens as the progesterone levels drop?
Corpus luteum degenerages, endometrium breaks down, removes the inhibition preventing contraction of the uterus and starts the bleeding and cramps of menstruation.
How long do you take monophasic combination pills for?
How long do you take triphasic combination pills for?
21-24 days, followed by 4-7 days of a placebo drug
Give some adverse affects of the combined oral contraceptive pill.
DVT, MI, increased BP, gall stones, headaches, mood swings, increased risk of stroke.
What is the role of the progesterone only pill?
Causes cervical mucus to thicken.
When are POPs recommended?
Risk factors for venous thromboemboli, smokers, hypertensive, breast-feeding patients, smokers etc.
What are the two types of emergency contraception?
1) Up to 72 hours post-coitus = levonelle.
2) Up to 120 hours post-coitus = Ullipristal acetate, which is a selective progesterone receptor modulator.
Give three actions of oestrogen
-Increases sodium and water retention
-Raises HDL and lowers LDL
-Decreases bone reabsorption
-Impairs glucose tolerance
-Increases blood coagulability
Give three side-effects of oestrogen
-Water retention and weight gain
-Risk of breast and endometrial cancer
Give three actions of progesterone
-Increases bone mineral density
Give three side effects of progesterone
Give three side effects of testosterone
-Induce male secondary sex characteristics
How are sex steroids transported?
Whilst bound to sex-hormone binding globulin and albumin. (SHBG production is up-regulated by oestrogen).
Which sex steroids bind to which receptors?
-Oestrogen = ER-alpha and ER-beta
-Progesterone = PR-alpha and PR-beta
-Androgens = AR-1 and AR-2
When is the typical age of menopause?
What is premenopause?
The years leading up to the last period, when the levels are reproductive hormones are becoming more variable and lower.
What is perimenopause?
The menopause transition years, before and after the date of the final episode of flow. Can last for 4-8 years. Oestrogen levels are around 20-30% higher than during premenopause.
Give an indication for hormone replacement therapy.
-Post-menopausal women with symptoms such as vasomotor instability and vaginal atrophy.
Give three risks of hormone replacement therapy.
1) Increased risk of endometrial/ovarian cancer
2) Increased risk of stroke
3) Increased risk of DVT
Give two examples of selective oestrogen receptor modulators .
What are SERMS?
Agonists or antagonists of oestrogen receptors.
How does clomiphene work?
It is a partial oestrogen agonist and interferes with oestrogen negative feedback on the hypothalamus. This therefore increases secretion of gonadotrophin-releasing hormone, therefore stimulation of ovulation.
What are anti-progestins used for?
Medical termination of pregnancy and induction of labour.
What are anti-androgens used for?
Benign prostatic hyperplasia and prostate cancer.
How does atherosclerosis form?
Calcium deposits between the muscular wall and the outer portion of the atheromatous plaques. This interferes with calcium deposition, it accumulates and crystallizes.
Cholesterol delivered into the vessel wall.
Foam cells and platelets encourage proliferation of smooth muscle cells, when then ingest lipids, replaced by collagen and become foam cells themselves.
A fibrous cap forms between fatty deposits and the artery lining (atheromas).
These atheromas produce enzymes causing the artery to enlarge over time.
How do statins reduce LDL cholesterol?
Competitively inhibit HMG-CoA reductase. They cause a lowering of intracellular cholesterol, causing the cell to increase its level of LDL receptors and remove cholesterol from the blood plasma.
Give 2 ADRs of statins.
-Increased liver enzymes
-Myopathy and rhabdomyolysis
-Increased effects of warfarin
Give 2 benefits of statins.
-Improved coronary endothelial function
-Inhibition of platelet thrombus formation
How do Cholesterol lipase inhibitors reduce LDL cholesterol?
E.g. Ezetimibe. Selectively inhibit absorption of dietary and biliary cholesterol in the small intestine, hence decreased transport of intestinal cholesterol to the liver. This increases cholesterol clearance from the blood.
How does Nicotinic acid reduce LDL cholesterol?
Also increases HDL-C. Strongly inhibits lipolysis in adipose tissue, hence reduced production of free fatty acids, and reduced TAG synthesis.
Give 2 ADRs of nicotinic acid.
-Cutaneous flush and pruritis
-Nausea and abd. pain
-Hyperuricaemia and gout
-Impaired glucose tolerance
How do fibrates reduce LDL cholesterol?
e.g. fenofibrate. They are peroxisome proliferator-activated receptor agonists. They decrease TAG concentration by increasing expression of lipoprotein lipase, and used to treat hypertriglyceridaemias.
How do Resins reduce LDL cholesterol?
Bind to negatively charged bile acids and bile salts in the small intestine. This complex is then excreted, lowering the bile acid concentration. Hepatocytes then convert cholesterol to bile acids. Hence increasing hepatic uptake of cholesterol containing LDL particles.
What is combination therapy in terms of reducing LDL cholesterol?
Usually involves a statin plus either a fibrate, nicotinic acid, ezetimide or omega03 fatty acid.