Estrogens Flashcards
What does estrogen do in the body?
development and maintenance of female reproductive tissues; regulation in CNs; effects in peripheral tissues
What does progesterone do in the body?
Development and maintenance of female reproductive tissues; maintenance of pregnancy; effects in other tissues (brain)
Most potent estrogen in humans
17beta-estradiol
Where is 17b-estradiol produced?
mostly in the ovaries in premenopausal women; synthesized most in the placenta during pregnancy
Estrogen and progesterone are produced by
granulosa cells and the corpus luteum
Early follicular phase
estrogen suppresses the production of FSH
Late follicular phase
Estrogen and progesterone stimulate the surge of LH and FSH -> ovulation and formation of the corpus luteum
Luteal phase
Estrogen and progesterone suppresses the production of LH and FSH
What happens if pregnancy does not occur?
corpus luteum degenerates; production of estrogen and progesterone by corpus luteum declines
What happens if pregnancy occurs?
fertilized egg/embryo secretes hCG; hCG acts like LH to stimulate corpus luteum to produce progesterone during the first trimester; higher progesterone levels support maintenance of the endometrium
Estron and estriol are synthesized
in the liver and in peripheral tissues
Natural estrogens
17beta-estradiol
Estrone
Estriol
Synthetic estrogens
Drugs with estrogenic activities
Phytoestrogens
Estrogen-mimetic compounds in plants (flavonoids)
Environmental estrogens
Compounds used in the manufacture of plastics (bisphenols, alkyphenols, phthalate phenols)
Metabolism and excretion of estrogen
Metabolized in the liver mostly and excreted to the bile and to the urine
Physiologic effects of estrogen
Female maturation, endometrial effects, metabolic and CV effects, blood coagulation, CNS/mood
Clinical uses of estrogens
Postmenopausal hormone therapy in post-menopausal women, osteoporosis
Adverse effects of estrogens
Uterine bleeding, endometrial carcinoma, breast cancer, thromboembolism, nausea, headache, fluid retention, weight gain
17alpha-alkylated estrogens
Mestranol;
Quinestrol;
Ethinyl estradiol
17alpha-alkylation prevents
conversion to estron -> enhances oral bioavailability and increases the half life
Estrogenic esters
Estradiol valerate
Estradiol cypionate
Esterification decreases
solubility and slows the absorption -> prolongs the action
Conjugated estrogens
Estrone sulfate
Equilin sulfate
Where do you get conjugated estrogens from
collected from pregnant mare urine
Non-steroidal estrogens
Diethyl stilbestrol
Chlorotrianisene
Diethyl stilbestrol
used in advanced prostate cancer
Chlorotrianisene
postpartum breast engorgement; menopause symptoms; prostate cancer
Selective estrogen receptor modulators (SERM)
Tamoxifen
Toremifene
Raloxifene
Clomiphene
Tamoxifen
partial estrogen agonist; antiestrogen and estrogenic actions; treatment of breast cancer; prevents breast cancer in high risk women
Raloxifene
SERM; partial estrogen agonist; prevents osteoporosis; decreases LDL levels; increases risk for blood clots; does not stimulate endometrial cells; may cause hot flashes
Clomiphene
SERM; partial estrogen agonist; increases secretion of FSH and LH by inhibiting negative estradiol feedback; used to sitmulate ovulation in women with oligomenorhea or amenorrhea and ovulatory dysfunction; polycystic ovary syndrome
Fulvestrant
selective estrogen receptor downregulator; pure estrogen receptor antagonist
Aromatase inhibitors
Anastrozole, Letrozole, Exemestane
