EXAM #5: ESTROGENS & PROGESTINS Flashcards
What regulates steroidogenesis in the ovary?
Gonadotropins (LH and FSH)
What cells are required for estrogen synthesis in the ovary?
Theca and granulosa cells
What is the two-cell hypothesis in steroidogenesis in the ovary?
LH= increased androstenedione synthesis in Theca cells
- andorstenedione is then made into testosterone
FSH= stimulates testosterone–>estradiol conversion in the granulosa cells
How will estrogen and progesterone alter GnRH release?
Negative feedback
When does positive feedback occur with estrogen and progesterone ?
Mid-ovarian cycle i.e. day 14
*Positive feedback= increased LH necessary for ovulation
What are the three phases of the menstrual cycle?
1) Follicular
2) Ovulation
3) Luteal
What happens during the follicular phase of the menstrual cycle?
- ESTROGEN rises
- Endometrial cell proliferation occurs
What happens during ovulation?
Estrogen-mediated positive feedback on LH leads to a LH spike that causes ovulation
What happens during the luteal phase of the menstrual cycle?
- Rise in estrogen and progesterone, but MOSTLY PROGESTERONE
- Progesterone control differentiation of the endometrial lining for implantation
What happens if implantation does not occur during the menstrual cycle?
Steroidogenesis is NOT maintained and endometrial lining is shed
What is the MOA of endogenous steroids to produce a physiologic effect?
Bind intracellular receptors and modulate trascriptional activity
Where do endogenous steroid agonists and antagonists compete?
Steroid binding sites
How do progesterone and estrogen differ in regards to their effect on the endometrium?
Estrogen= proliferation
- Follicular phase
Progesterone= differentiation to prepare for implantation
- Luteal phase
What are the metabolic effects associated with estrogen in regards to lipids, bone, liver, and blood?
Lipids= decrease LDL and increase HDL
Bone= antiresorptive
Liver= increased plasma proteins
Blood= increased coagulation factors and decrease antithrombin i.e. PROCOAGULANT
What are the metabolic effects associated with progesterone in regards to lipid and glucose?
Lipids= increase LDL and fat deposition
Glucose= increased fasting glucose
What effect does progesterone have on uterine contraction?
Progesterone DECREASES uterine contraction
How does progesterone decrease uterine contraction?
1) Decreased prostaglandin production
2) Maintenance of relaxin
What effect does progesterone have on cervical glands?
Increased cervical mucous viscosity
*This impairs the sperm ability to swim
What is the primary natural estrogen?
Estradiol
What is the primary synthetic estrogen? What are these drugs used for?
Ethinyl estradiol
*Also, Mestranol both of which are used for birth control
What is diethylstilbestrol?
Non-steroid synthetic estrogen-mimic
*Not used in clinically practice but important for boards
What advantages are seen with synthetic estrogen vs. endogenous estrogen?
1) Increased half-life
2) Decreased first pass effect
This is advantageous from a compliance standpoint
What are conjugated equine estrogens? How are these used clinically?
Natural water-soluble estrogen sulfates
- Higher dose vs. synthetics
- Used for hormone replacement therapy
What are the clinical indications for estrogen therapy?
1) Hypogonadism
2) Hormone replacement therapy
3) Contraception
4) Acne
