Estrogen and Progestins Flashcards
1
Q
Estrogens
A
- 17B Estradiol = E2 = Estrogen
- Most affinity for receptor
- Major secretory from ovary
- Synthesized from androtenedione or testosterone - Estriol - metabolite of estradiol
- principle placental estrogen, pregnancy - Estrone - metabolite of estradiol
- metabolite of estradiol, ovaries
2
Q
Progesterone
A
- precursor to androgens and estrogens
- secreted by corpus luteum (ovulated follicles)
3
Q
Weak Female Androgens
A
- DHEA and androtenedione
- Small amounts of testosterone
4
Q
Estrogen Hormone Levels
A
- Follicular: 200 pg/mL
- Ovulation: 1000 pg/mL (peak level)
- Luteal: 500 pg/mL
- Pregnancy: 20,000 pg/mL
- Menopause: 5-20 pg/mL
5
Q
Progesterone Hormone Level
A
- Follicular: <1.5 ng/mL
- Ovulation: <1.5 ng/mL
- Luteal: 35 ng/mL
- Pregnancy: 150 ng/mL
- Menopause: <0.4 ng/mL
6
Q
Follicular Phase
A
- Menses: endometrium shedding
- FSH increases early and stimulates estrogen production (+LH) - follicular recruitment/growth (6-12 follicles)
- Day 6 - one follicle dominates and secretes estrogen which inhibits FSH and follicle development
- Increases LH receptors late in cells and granular cells to produce progesterone
- Ovulation 24-36 hours after estrogen peak and LH surge (ovulation tests)
- Oocyte has ~24 hours to be fertilized or DEATH
7
Q
Luteal Phase
A
- Corpus luteum (follicle remnant) - estrogen and progesterone secretion increases
- FSH and LH inhibited
- Consistently last 14 days to thicken endometrium and mucus for implantation
- Not pregnant? Corpus luteum reaches peak steroid production at about day 7 and degenerates, hormone levels drops and period start
- Pregnant? Produces HCG (pregnancy tests) which sustains pregnancy by stimulating the corpus luteum to continue secreting progesterone/estrogen (placenta takes over at end of first trimester, high risk of miscarriage)
8
Q
Steroids
A
- Made from cholesterol
- Carried in blood bound to carrier proteins
- Passes through cell membranes
- Bind to steroid receptors
- Estrogen receptors: ERalpha/ERB
- Progesterone receptors: PR B (main) and PR A
9
Q
Estrogen MoA
A
2 different receptors for estradiol:
- ERalpha - uterus, mammary gland, ovary, bone, liver, and adipose
- ERB - ovary (granulose cells), colon, adipose, and immune system
* *2/3 of breast cancers express ERalpha, drug target**
10
Q
Estradiol Functions
A
- Uterine/menstrual cycle
- Development of secondary characteristic
- Bone
- Lipid metabolism
- Blood vessels
- Liver
- CNS
11
Q
Uterine/Menstrual Cycle
A
- Stimulates proliferation of endometrium
- Increase progesterone receptor in endometrium
- Increase sensitivity to oxytocin leading to increased uterine motility
- Increase level prior to ovulation stimulate LH surge to cause release of follicle
- Decrease viscosity of secretions in cervix
- Also watery, alkaline secretions good for sperm survival
- Inhibits GnRH, FSH, and LH - main mechanism for contraception
12
Q
Development of Secondary Sex Characteristics
A
- Growth/development of labia, vagina, cervix, Fallopian tubes, and uterus
- Breast enlargement, pubic hair, skeleton shaping, growth spurts, fusion of epiphyses
13
Q
Estrogen + Bone
A
- Osteoclasts block resorption of bone
- Balance leans toward osteoblast which increases bone formation but NOT direct effect
14
Q
Lipid Metabolism + Estrogen
A
- Mainly beneficial
- Increased serum TG and HDL
- Decreased TC and LDL
15
Q
Blood Vessels
A
- Promotes vasodilation by increased NO synthase
- Stimulates renal Na+/H2O retention
- Promotes vascular healing by increasing endothelial cells and decreasing smooth muscle proliferation
- Inhibits development of atherosclerosis
16
Q
Liver + Estrogen
A
- Stimulates production of many proteins
- Hormone binding proteins increases
- Clotting factors increase and may cause thromboembolic disorders
17
Q
CNS + Estrogen
A
- Neuroprotection
- Increase vasodilation and decreases vascular inflammation
- Protect against stroke
- Mood, cognition
18
Q
Progesterone Functions
A
- Thicken uterine lining for fertilized eggs for uterine differences
- Antagonizes estrogen-driven growth in endothelium and decreases myometrial contactility
* *Prepares and maintains pregnancy**