Women Contraception Flashcards
Estrogen and progestins are used for
Contraception
Ovulation induction
Hormone replacement therapy
Cancer replacement therapy
Gonadotripic-Releasing Hormone (GnRH) is a
PEPTIDE hormone (amino acids structure)
FSH regulates/stimulate:
Follicles growth and maturation
Steroidogenesis (Cholesterol side chain cleavage & aromatase activity in granulosa cells.)
Granulosa cells are
Intracellular
Theca cells are
Extracellular
Corpus Luteum produce
progesterone (until placenta begins take over)
Aromatase also named:
Estrogen synthase
Aromatase activity
convert Testosterone to Estradiol
LH act on
Theca cells
LH regulate/stimulate:
Steroid synthesis
FSH receptors
Steroidogenesis pathway:
Cholesterol –> (side chain cleavage reaction) –> progesterone –> testosterone –> (aromatase reaction) –> estradiol.
Two estradiol receptors:
human estrogen receptor alpha (hER alpha)
‘’ beta (hER beta)
Estrogen action
bind to lipophilic p+ in circulation –> enters cells –> interact with hER (receptor) in nucleus or cytoplasm –> DNA target genes.
Difference between ER alpha and beta isoforms
different response elements (ligand)
different co-activators
Beta isoforms have other mechanisms like non-genomic mechanisms
Effect of estrogen:
Local effects: Myometrium, Uterus, In the brain (control temperature, moodiness)
System effects: p+, carbohydrate and lipid metabolism, water and electrolyte balance, blood clotting, fat distribution, bone maturation…
Progesterone action:
Bind to hPR –> interact with the progesterone response element in DNA –> affect genes
Non-genomic pathway of progesterone
progesterone bind to membrane receptor–> activate secondary messengers intracellular –> biological function
(MORE RAPID THAN USUAL ACTION)
Exemple of hPR post-transcriptonally modified:
alternatively spliced (generate hPR alpha & beta isoform)
Major functions are similar. The difference in the role of Progesterone is
It antagonizing the action of estrogen in the fallopian tubes and on myometrium.
What lead to a dramatic surge of LH?
When the FSH decreases.
What stimulate the ovulation of the mature follicule>
LH surge
After ovulation what happen to LH and FSH?
LH goes down
FSH restores back to normal.
When is the progesterone rise:
Low level 1st to 14th days of menstrual cycle and rise after.
What is the Combination oral contraception:
Leveonorgestrel (analogue progesterone) Ethinyl Estradiol (analogue estradiol)
Mechanism of action of the oral contraceptive pills
Maintain constant level of estradiol so prevent the surge of estradiol –> prevent the surge of LH (INHIBIT OVULATION)
Estrogen positive feedback (increase level of LH and FSH) occurs when?
it is at high concentration (near end of the follicular phase)
Midcycle LH surge stimulate
mature follicule rupture and ovulation (occyte)
Mechanism of action of oral pills at different levels:
Regulate higher brain centers Hypothalamus: decrease GnRH pulses Pituitary: decrease responsiveness, supresses FSH release and follicule growth/developpment Follopian tube Ovary Endometrium Cervial mucus.
Oral contraception absolute contra-indication:
History of breast cancer History of blood clot Liver or Kidney disease Unexplained uterine bleeding Smoker over age of 35
Morning after pill mechanism of action:
Block fertilization or Block the implantation!
Need to be take when?
In 72hours!
Plan B differentiation of other morning pills?
only progestin pills
Ulipristal acetate is
a selective progesterone receptor modulator (SPRM)
Act as an Antagonist/agonist (mixed reaction)
Estrogen and progesterone are metabolized by?
Cytochrome P450 enzymes
Drugs that can interacte with P450 enzymes are?
Because?
Barbiturates
Phenytoin
Rifampicin (anti-bacterial drugs)
bc they are inducer of P450
So contraception drugs are more metabolized, less efficace.
Why broad-spectrum antibiotics such as Ampicillin, tetracycline and Neomycin can decrease efficacy of oral contraception?
Bc Kill intestinal bacteria in the GI tract
(Glucuronidases present in the bacteria flora to breakdown glucuronides) –> Oral pill are reabsorbed with the recycling of biles acids.
Glucuronides is make by
and is made into?
Liver
conjugates
