Week 4: Estrogen and Progesterone

effects of estrogen and progesterone

sexual differentiation, go quiet until puberty, and then initiate menstruation

which action is more? estrogen/progesterone

estrogen

progesterone is involved in

facilitating and maintaining pregnancy

follicular phase length

1-13 days

luteal phase length

15-29 days (always 14)

menses is considered cycle day

1

follicular phase

pituitary releases FSH and causes maturation of ovarian follicles, also release estrogen leading to endometrial thickening

ovulation phase

just prior to ovulation pituitary releases LH which causes ovulation, ovum becomes corpus luteum (CL)

luteal phase

LH and FSH decrease, CL secretes estrogen and progesterone and thickening of endometrium, if egg isnt fertilized it doesnt implant so CL decreases, CL stops producing estrogen and progesterone

endometrium sloughs means

menstruation (in luteal)

positive feedback loop

increased estrogen at end of follicular phase signals hypothalamus to release GRH and triggers LH release for ovulation

increased levels of estrogen do what to hypothalamic-pituitary axis

turns it on

negative feedback loop

secretion of LH and FSH is inhibited toward end of luteal phase because of sustained estrogen and progesterone turns off hypothalmus pituitary axis

fertilized ovum releasess

human chorionic gonadotropin (HCG)

how long is CL active in pregnancy

until 9th-14th week to produce progesterone

after week 14, what takes over estrogen/progesterone production

placenta

progesterone 2 functions in pregnancy

maintain uterus and placenta, develop mammary glands to prep for lactation

hormonal contraceptives use what hormones

estrogens and progestins administered in various ways

side effect of estrogen

nausea, vomiting, headache

side effect of progestin

weight gain, edema, depresion

mechanism of action for hormonal contraception

inhibit ovulation and impair normal development of endometrium, prevent formation of ovum, does not develop lining, increases viscosity of secretions to prevent sperm

why are contraceptives used to treat abnormal periods

so that endometrial lining doesnt develop

risks of contraceptives

VTE, ischemic stroke, MI

why is there a risk of VTE

impact of estrogen on liver synthesis of blood coagulation factors

what increases risk of VTE

over 35, smokers, clotting disorders

selective estrogen receptor modulators

raloxifine, tamoxifen

raloxifine

agonist activity on bone, antagonist on breast and endometrial tissue, treats OP

tamoxifen

antagonists in breast tissue, partial agonist in bone, agonist at endometrial estrogen receptors (increase risk of endometrial cancer, prevent breast cancer)

aromatase inhibitors

nonsteroidal inhibitor of aromatase that is normally required for estrogen synthesis

aromatase inhibitors are used in treatment of

breast cancer

megestrol (Megace)

progestin that mainly used as appetite stimulant and used for conditions with cachexia (weakness/wasting in end stage hiv/aids, cancer)