M2- lecture 14 reproductive system Flashcards
what is GnRH?
stimulates the secretion of FSH and LH from the ANTERIOR pituitary.
what does LH and FSH do?
they stimulate ovarian follicle development.
- FSH stimulates estrogen release.
- LH stimulates ovulation and controls progesterone secretion from the corpus luteum.
what does estrogen and progesterone do?
estrogen controls proliferation of the endometrium.
progesterone controls the later secretory phase.
what are the three endogenous estrogens?
estradiol (MOST POTENT)
estrone
estriol
what are the synthetic forms of estrogen ?
ethinylestradiol and mestranol.
how does estrogen work?
it acts via nuclear estrogen receptors (ER) alpha and beta (TRANSCRIPTION FACTORS).
may also act via GPCR (VASCULAR ACTIONS).
how does estrogen receptor singling work?
1) most actions are mediated via nuclear ER alpha and beta. they are transcription factors that regulate gene expression.
2) VASCULAR ACTIONS via GPCR also known as GPR30. –> activates NO synthase (enos) increases NO causing vasodilation.
what are two main types of hormonal contraceptive?
1) combined pill
2) the progesterone only pill
whats the combined pill?
it has both estrogen and progesterone.
what are the adverse effects of the combined pill?
Acne (from the progesterone component of the combined pill)
THROMBOEMBOLISM (obstruction of blood vessel) –> rare.
reduction in risk of ovarian and endometrial cancer because u can detect it earlier.
whats the MOA of the progesterone only pill ?
- acts primarily on the cervical mucus making it inhospitable to the sperm.
- also inhibits implantation through its action on the endometrium and by altering motility and secretions of the fallopian tubes.
what are the adverse effects of the progesterone only pill?
- irregular bleeding are common.
- less reliable at contraception than the combined pill
- less overall safety data.
who is suitable for the progesterone only pill?
people who experience blood pressure increases resulting from estrogen or other contraindications of estrogen.
what is postcoital contraception? (progesterone based)
postcoital (emergency) contraception. its an oral administration of LEVONORGESTREL.
effective up to 72 hours post-unprotected intercourse with a repeated dose 12 hours later.
nausea and vomiting are common. CAN BE TAKEN WITH GRAVOL
what is long acting progestogen only contraception?
intramuscular depot medroxyprogestogen
infertility may persist for months after stopping treatment.
whats are agents that enhance uterine motility?
- OXYTOCIN
- ergometrine
- mifepriston/misoprostol.
CERVICAL RESISTANCE MUST DIMINISH FOR UTERINE CONTRACTIONS TO BE EFFECTIVE AT DRIVING UTERINE CONTENTS THROUGH THE CERVIX.
how does oxytocin work?
oxytocin receptors is a GPCR (Gq) that promotes increases in intracellular calcium (by IP3).
activation of calmodulin (CaM) stimulates myosin light chain kinase (MLCK) to induce uterine contraction.
what are some side effects of oxytocin?
- hypotension (when administered rapidly)
- higher doses can cause sustained contractions reducing blood flow and o2 delivery to the placenta that leads to fetal distress and potentially death.
what is ergometrine ?
a drug that acts on the uterus.
whats the MOA of ergometrin?
- acts on the uterine smooth muscle is not completely understood.
may act partly on the alpha adrenoceptors and partly on 5-HT (serotonin) receptors.
whats the adverse effects of ergometrin?
vomitting (D2 receptors in the chemoreceptors trigger zone).
whats are 2 drugs that can inhibit uterine motility?
atosiban and salbutamol
whats are the drugs that are used for erectile dysfunction?
PHOSPHODIESTERASE TYPE V (PDE V) inhibitors.
- sildenafil (viagra)
- tadalafil (longer acting0
- vardenafil (more selective for PDEV)
whats are some adverse effects for the drugs used for erectile dysfunction?
- hypotension
- visual disturbances (inhibition of the PDE VI).
what are some adverse effects of the drugs used to treat infertility?
- flushing, vaginal dryness, bone loss and reversible ovarian enlargement (prob wont be tested tho)
