Final Exam- Hormones of Reproduction Pt 2 Flashcards
What converts testosterone into 17beta-estradiol? What cells does this occur in?
What stimulates this enzyme?
aromatase (in granulosa cells in ovaries)
FSH
What are the two enzymes the ovaries have that are important?
- 17beta-hydroxysteroid dehydrogenase
2. Aromatase
What convertes androstenedione to testosterone in the ovaries? What other organs have this enzyme?
17beta-hydroxysteroid dehydrogenase
testes
(adrenal lack it)
What is the major ovarian estorgen?
17beta-estradiol
What does aromatase do in the ovaries? Can the testes produce this?
converts testosterone into 17beta-estradiol
testes produce a little too
What do the Theca cells of the ovaries produce and secrete?
progesterone
as well as androstenedione
What does androstenedione produced and secreted by Theca cells do?
diffuses from theca cells to granulosa cells –> which in presence of 17Beta hydroxysteroid dehydrogenase is converted into testosterone
which in presence of aromatase is converted to 17beta-estradiol
What stimulates cholesterol desmolase in theca cells in the ovaries?
LH
What stimulates aromatase in granulosa cells in the ovaries?
FSH
What are the two major functions of the ovaries? What are both of these functions controlled by?
- oogenesis
- synthesis/secretion of female sex hormones
hypothalamic-pituitary axis
Where is GnRH secreted from? What will it stimulate when it is delivered to the Ant. Pit. in high concentrations?
from hypothalamus
stimulates pulsatile secretion of FSH/LH which act on the ovaries
What is the effect of FSH/LH on the ovaries?
- follicular development–> leads to ovulation
- synthesize/secretion of progesterone and 17beta-estradiol
How long is the menstrual cycle?
28 day cycle
follicular development–> ovulation–> formation and degeneration of corpus luteum
What is the first 14 days of the menstrual cycle called? What is the midpoint of the cycle? What is the last 14 days called?
Follicular phase
ovulation
Luteal phase
What occurs during the Follicular phase? What hormone dominates?
development of follicle
estrogen (17beta-estradiol)–> gets uterus ready for pregnancy
What occurs during the luteal phase?
dominated by corpus luteum
What are the only ovarian cells with FSH receptors? What does FSH stimulate of these cells?
Granulosa cells –> FSH stimulates growth of them in primary follicles–> stimulates estradiol synthesis
What supports the trophic effect of FSH on granulosa cells?
estradiol
What initiates ovulation?
LH
What occurs just prior to ovulation?
just prior to ovulation LH rises sharply and causes rupture of the mature follicle (ovulatory surge)
What stimulates the formation of the corpus luteum? What else does this hormone do?
LH
maintains progesterone production by the corpus leuteum during the luteal phase
What maintains progesterone production by the corpus leuteum during the luteal phase?
LH
During the menstrual cycle, what two levels does feedback occur at?
- Anterior pituitary
2. Hypothalamus
What hormone is the main product in the Follicular phase?
What is the main hormone in the Luteal phase?
17beta-estradiol
Progesterone
During the Follicular phase, what effect will 17beta-estradiol have on the Anterior pituitary and hypothalamus?
inhibitory effect (negative feedback)
therefore less FSH/LH secretion
During midcycle of the menstrual cycle, what effect will 17beta-estradiol have on the Anterior pitutitary and hypothalamus?*
stimulatory effect (positive feedback)
therefore increase in GnRH release and therefore increase in FSH/LH
= ovulatory surge
During the Luteal Phase, what effect with progesterone have on the anterior pituitary and the hypothalamus?
inhibitory effect (negative feedback)
therefore less secretion of FSH/LH
What is required for maintenance of pregnancy?
progesterone
keeps uterus “quite” during pregnancy
Which precedes what in the course of the menstrual cycle…estrogen or progesterone?
estrogen precedes progesterone
What effect will estrogen have on progesterone receptors in target tissues?
it up regulates them
What effect does progesterone have on estrogen receptors in some target tissues?
down regulates them
therefore decreases responsiveness to estrogen
In general what is the ratio like b/w estrogen and progesterone?
much higher progesterone to estrogen levels (150:1)
When estrogen dominants over progesterone, what is this due to?
due to progesterone levels FALLING (not so much due to estrogen levels rising)
What effect does estrogen have on the uterus?
What about progesterone?
estrogen–> causes cell proliferation, cell growth, and increase contractility
progesterone–> increase secretory activity and decrease contractability
What effect does estrogen have on the uterine tubes?
What about progesterone?
estrogen–> + ciliary activity and contractility (aids movement of sperm towards uterus)
progesterone–> increase secretory activity and decrease contractility
What effect does estrogen have on the cervix?
What about progesterone?
estrogen–> causes cervical mucous–> copious, watery, elastic
progesterone–> decreases quantity of cervical mucous and become thick, non elastic
What effect does estrogen have on the vagina?
What about progesterone?
estorgen–> + proliferation of epithelial cells
progesterone–> + differentiation but inhibits proliferation of epithelial cells
What is useful as a marker of ovarian reserve and can predict reproductive lifespan for a female?
Anti-Mullerian hormone
is a good measure of fertility
What happens to Anti-Mullerian hormone with age?
declines with age, as egg supply diminishes
What hormone does development of mammary glands require?
estrogen
What does estrogen stimulate in mammary glands?
- growth of lobular ducts
- enlargement of areola
- increase amount of adipose tissue
What works synergistically with estrogen to stimulate secretory activity in lobular ducts of mammary glands?
progesterone
What are lobular ducts of mammary glands lined with?
milk-secreting epithelium
When do the highest levels of estrogen and progesterone occur?
during pregnancy
When is the period of highest progesterone output by the corpus luteam occur?
day 5 after ovulation
At what days does the following occurs?1
- fertilization
- entrance of blastocyte into uterus
- implantation
- attachment of endometrium
- secretion of HCG
- HCG rescue of corpus luteum
- day 1
- day 4
- day 5
- day 6
- day 8
- day 10
What two things does the blastocyst consist of?
- inner mass of cells–> become fetus
2. outer mass of cells–> trophoblast (contributes to fetal portion of placenta
What does the trophoblasts part of the blastocyst do?
invades endometirum and attaches and will contribute to the fetal portion of the placenta –> will begin secreting HCG ~ day 8
What will take over/ maintain the function of the Corpus Luteaum during pregnancy?
HCG; from the trophoblasts (outer rim of cells of the blastocyst) invading endometrium and contributing to fetal part of placenta
What would happen to the Corpus Luteum without HCG?
it would regresses (day 12) and menses occurs
What hormone increases dramatically during the first weeks of pregnancy and is the basis of pregnancy tests? What day is it detectable in the urine?
HCG
day 9
Describe the fluctuation of HCG in the first trimester of pregnancy? What is its interaction with the Corpus Luteum?
increases sharply and peaks ~ wk 9 and then decreases
rescues corpus luteum; and stimulates Corpus luteum to produce Estrogen and Progesterone
What does HCG stimulate the Corpus Luteum to produce?
Estrogen and progesterone
What has happened to HCG during the second and third trimesters of pregnancy?
has fallen off
What takes over production of steroid hormones during pregnancy?
placenta
What is the major estrogen during pregnancy? What does its production require?
Estriol
cholesterol from mother and both fetal adrenal cortex and fetal liver
(requires mother, placenta, and fetus)
What happens to the levels of Estriol during pregnancy?
levels rise throughout until parturition
What accounts for the steep rise of estriol in maternal blood during last weeks of pregnancy?
fetal dehydroepiandrosterone-sulfate (DHEA-5)
What does progesterone require during pregnancy to be made? How do the levels change throughout pregnancy?
cholesterol from mother (requires mother and placenta only–NOT fetus)
levels rise until parturition
What is the precursor for progesterone?
pregnenolone (and precursor for that is cholesterol)
What is produced by the anterior pituitary throughout pregnancy?
Prolactin
What hormone stimulates prolactin? How do the levels of prolactin change throughout pregnancy?
estrogen
levels gradually and steadily rise
What is the hormone of highest concentration during the last half of pregnancy?
Prolactin
What suppresses lactation during pregnancy? Why does lactation begin at parturition?
Estrogen and progesterone suppress lactation
lactation begins at parturition when Estrogen and progesterone levels drop
What drives the fetal pituitary-adrenal axis to produce significant amounts of cortisol? Where is this hormone produced?
Corticotropic Releasing Hormone (CRH)–> produced by placenta
What is an important function to cause maturation of the lungs of the fetus to allow them to produce surfactant?
cortisol
What hormone from the placenta stimulates the formation of both PGF-2alpha and PGE (prostagladins) during pregnancy?
Corticotropic Releasing Hormone (CRH)
What week does delivery of the fetus normally occur?
week 40
What happens to the myometrium and cervix during parturition?
myometrium–> forceful coordinated contractions
cervix–> softens and becomes distensible
B/w estrogen and progesterone, which becomes dominant during parturition?
estrogen becomes dominate due to decreases in progesterone
What are 5 important hormones during parturition?
- Cortisol
- Estrogen
- Relaxin
- Prostaglandins
- Oxytocin
What will fetal cortisol cause near parturition?
increase estrogen/progesterone ration (estrogen dominate due to drop in progesterone)
there increases sensitivity of uterus to contractile stimuli
What hormone stimulates the production of PGE-2 and PGF-2alph during parturition?
Estrogen (estriol)
What is produced by the corpus luteum and relaxes the pubic ligament and softens the cervix?
relaxin
What hormones cause rupturing of fetal membrane and softening of the uterine cervix and contraction of myometrium?
Prostaglandins (both PGF-2alpha and PGE)
What stimulates both placental production and fetal production of CRH –> ACTH –> cortisol?
Prostaglandins
```
CRH = Corticotropin releasing hormone
(ACTH = Adrenocorticotropic hormone)
~~~
What hormone is used clinically to induce labor?
oxytocin
What stimulates powerful slow and prolonged contractions of the uterine myometrium at the end of pregnancy?
Oxytocin
T/F. Oxytocin is the physiologic trigger for parturition?
FALSE– it is NOT the physiologic trigger for parturition–> levels don’t increase until after labor has begun
What is oxytocin secreted in response to?
as a neuroendocrine reflex in response to stretching of uterus
What protects against hemorrhage after expulsion of the fetus?
Oxytocin
T/F. no signle even appears to initiate parturition.
true
What happens to progesterone levels after loss of placenta?
What about its effect prior to parturition?
they DO NOT decline
there is a decrease in progesterone effectiveness prior to parturition
After delivery of the placenta, all hormone concentrations return to their pre-pregnant levels except which one?
prolactin–> which will remain high if mother breast-feeds infant
How is lactation maintained?
by suckling
What does suckling stimulate the secretion of?
both oxytocin and prolactin
What hormone induces milk “let down”? What hormone stimulates milk production?
“let down” = oxytocin
produciton = prolactin
What suppresses ovulation after birth? What does this hormone inhibit?
prolactin release form continuing lactation by baby suckling breasts
prolactin inhibits GnRH and FSH/LH
T/F. Breast feeding is a method of contraception.
FALSE–not 100% effective
What hormones are Oral Contraceptives the combination of?
- Estrogen and Progesterone
2. Progesterone alone
What will an Oral Contraceptive of a combination of Estrogen and Progesterone cause?
Causes:
- negative feedback on pituitary gland and inhibits FSH/LH
- cervical mucous to be hostile env. for sperm
- decrease motility of uterine tubes
What will an Oral Contraceptive of Progesterone alone cause?
Progesterone alone:
- effects on cervical mucous
- altered tubal motility
What is the name for the Morning After Pill? (maybe what drug is used) What does it contain a higher dose of?
Postcoital
- higher does of estrogen/progesterone (interferes with implantation)
- Mifepristone–> antagonist to progesterone receptor–> prevents implantation
What does Menopause mean and what age does this occur?
cessation of menstrual cycle
age 50
What occurs several years prior to menopause?
anovulatory cycles are common (Perimenopause)
– decrease number of functioning ovarian follicles
What are the signs and symptoms of menopause due to?
lack of estrogen
its secretion gardually decreases and eventually ceases
What are signs and symptoms of menopause?
- thinning of vaginal epithelium
- decrease vaginal secretions
- decrease breast mass
- increase bone loss
- vascular instability (“hot flashes”)
- emotional lability
Who tend to be less symptomatic during menopause, obese women or non-obese women? why?
obese women—-> due to androgenic precursors and aromatase present in adipose tissue
What are benefits of hormone replacement therapy? Is this still routinely recommended for women in menopause?
- relief of menopausal symptoms
- protection against osteoporosis
- decrease risk of colorectal cancer
(NOT longer routinely recommended for menopausal symptoms)
What are risk factors for hormone replaement therapy?
increase risk of:
- heart disease*
- breast CA*
- stroke
- blood clots
- abnormal mammograms, false positives
- = only seen in women taking estrogen along with progestin
What is it called when the father experiences physical symptom’s during mates pregnancy?
Couvade syndrome “sympathetic pregnancy”
- may have indigestion, weight gain, constipation/diarrhea, HA
Can male hormone levels be affected by their mates pregnancy? If so, how (what increases and what decreases)?
yes
- in last trimester testosterone decrease by 33%, and
- prolactin increases by 20%
–> prolactin will stimulate connections in brain for paternal behavior and decrease sex drive
