Reproduction

Question 1

What is the major circulating estrogen in premenopausal women? Major in men and postmenopausal women?

Answer 1

• premeno: estradiol

- men/postmeno: estrone

Question 2

What is aromatase’s role in hormone availability?

Answer 2

• converts testosterone to estradiol

- converts androstenedione to estrone

Question 3

How does estrogen reach and work on the target cell?

Answer 3

• travels through blood attached to sex hormone binding globulin
• crosses cell membrane and binds to heat-shock protein in cytoplasm
• enters nucleus and dimerizes to regulate gene expression

Question 4

Where is estradiol metabolized?

Answer 4

• metabolized to estrone in liver

- inactive metabolites excreted in urine

Question 5

What is the method to use estrogen to prevent pregnancy?

Answer 5

• maintains steady levels of estrogen to inhibit positive feedback and prevent LH surge
• constant levels of estrogen also suppress FSH and prevent follicle maturation
• no ovulation occurs

Question 6

What are the adverse side effects of estrogen therapy?

Answer 6

• increased risk of stroke, DVT
• increased body fat
• increased salt and fluid retention (HTN)
• nausea, breast pain, vaginal bleeding, HA

Question 7

What are the contraindications of estrogen therapy?

Answer 7

pregnancy, breast or endometrial cancer, endometriosis, undiagnosed vaginal bleeding, thromboembolic disease, HTN, hepatic disease

Question 8

How does tamoxifen work and what is it used for?

Answer 8

• nonsteroidal
• antiestrogenic on mammary epithelium (used for ER+ breast cancer - use in high concentration because estrogen has a much higher affinity for ER than tamoxifen)
• pro-estrogenic on endometrium and bone (increases risk of endometrial cancer with prolonged use)

Question 9

What is the mechanism of clomiphene citrate?

Answer 9

• blocks estrogen binding in hypothalamus which inhibits ability to give negative feedback on gonadotropins
• increases secretion of gonadotropins and LH
• encourages ovulation

SE: hot flashes, multiple pregnancy

Question 10

What are the physiological functions of progesterone?

Answer 10

• stimulates endometrium to develop secretory glands and support fertilized egg implantation
• growth suppressing effects on endometrial cancer
• high levels suppress ovulation

Question 11

Why are estrogen and progesterone often prescribed together?

Answer 11

• progesterone counters the endometrial stimulatory effects of estrogen and reduces the risk of endometrial cancer
• most effective form of contraception available, and reversible - can get pregnant 2-3 months after stopping

Question 12

What are the adverse effects of progestin therapy?

Answer 12

• strong androgenic activity (hirsutism, acne)
• edema, bloating
• anxiety
• irritability
• depression
• muscular pain
• increase risks of thrombosis and PE

Question 13

What is the mechanism of progestational contraception?

Answer 13

• suppresses LH and prevents ovulation
• thicken cervical mucus, making it inpenetrable to sperm
• develops endometrial atrophy

Question 14

What is the name of the drug used for emergency contraception?

Answer 14

levonorgestrel

- probably interferes with implantation and inhibits or delays ovulation

Question 15

What is the name of the abortion pill and how does it work?

Answer 15

• RU-486/mifepristone

- antiprogestin - causes breakdown of uterine lining and leads to detachment of embryo or fetus

Question 16

What are the drugs to treat erectile dysfunction and how do they work?

Answer 16

• saldenafil, vardenafil, tadalafil
• phosphodiesterase type 5 inhibitors (PDE5 expressed in corpus cavernosum and retina)
• SE: HA, dizziness, flushing, change in vision
• loss of vision: non-arteritic anterior ischemic optic neuropathy
• avoid using with nitrates and alpha blockers