Placenta endocrinology Flashcards
How long will a corpus luteum of menstruation last unfertilized? Fertilized?
9-10 days, up to 2 months when fertilized
6-7 weeks age of gestation, what organ is the major producer of progesterone?
Ovaries
When does placenta assume progesterone secretion?
8 weeks AOG
When does progesterone level reach 10-5000 times those found in non-pregnant women?
end of pregnancy
Enzyme that catalyzes conversion of cholesterol to pregnenolone? In what organelle does this occur?
Cytochrome 450, mitochondria
Enzyme that catalyzes conversion of pregnenolone to progesterone? In what organelle?
3-hydroxysteroid dehydrogenase, Endoplasmic reticulum
Preferred cholesterol of trophoblasts as a precursor to progesterone.
maternal LDL cholesterol
Precursor that fetus contributes for progesterone synthesis.
None
T/F trophoblasts have cholesterol.
F
Roles played by progesterone (4)
- prepares and maintains endometrium
- suppresses maternal immunologic response
- role in parturition
- substrate for adrenal gland production of glucocorticoids and mineralo corticoids
Amount of progesterone produced by the placenta at term per day
250mg/day
a hyperestrogenic state
near term, normal human pregnancy
Precursors for estrogen production comes from
maternal and fetal adrenal glands
Estrogen influences what? (4)
- progesterone production
- uteroplacental blood flow
- mammary gland development
- fetal adrenal gland function
The estrogen produced in greatest quantity during pregnancy.
Estriol
How is estrogen produced in ovaries?
androstenedione is produced in ovarian theca and then transferred to adjacent granulosa cells for estradiol synthesis
C19 steroids
DHEA and DHEA-S
Absent in placenta that’s why it can’t convert C21 steroids to C19 steroids?
17-hydroxylase
4 enzymes for placental conversion of C19 steroids to estradiol.
STS (dheas to dhea), 3HSD (dhea to androstenedione) , CYP19 (androstenedione to estrone), 17-hydroxysteroid dehydrogenase (estrone to estradiol)
Roles of estrogen (5)
- progesterone production
- increases blood volume
- vasodilatory effects
- mammary gland development
- fetal adrenal gland function
where is hCG produced?
almost exclusively in the placenta BUT ALSO IN FETAL KIDNEY
With highest carbohydrate content of any human hormone.
hCG (30%)
Effect of terminal sialic acid on hCG
protects hCG from catabolism
hCG is structurally related to which 3 other glycoprotein hormones?
LH, FSH and TSH
When is hCG molecule detectable in plasma of pregnant women?
7-9 days after LH surge that precedes ovulation
When is maximal level (100,000 IU/L) in maternal circulation is reached?
8-10 weeks of gestation
Functions of hCG (5)
- fetal testicular testosterone production
- stimulation of maternal thyroid activity
- promotion of relaxin secretion
- uterine vascular vasodilation
- myometrial smooth muscle relaxation
Events with lower hCG plasma levels (2)
- early pregnancy wastage
2. ectopic pregnancy
Events with high hCG plasma levels (4)
- multifetal pregnancy
- erythroblastosis
- gestational trophoblastic disease
- trisomy 21
Level of hCG when a gestational sac could be seen on transvaginal untrasound in viable pregnancies.
1000-1500 mIU/mL
Hormone produced in greatest amount by a pregnant woman near term, and amount.
hPL (1g/day)
Functions of hPL (4)
- maternal lipolysis
- anti-insulin (BUT DOES NOT INHIBIT INSULIN SECRETION)
- angiogenesis (fetal vasculature)
- mobilize lipids as free fatty acids
(Base results of fasting and feeding in these 4, so memorize by heart)
Stimulates release of placental ACTH
CRH (placental corticotropin-releasing hormone)
Where can relaxin be found? Function?
Corpus luteum, decidua and placenta
Enumerate 4 hypothalamic-like releasing hormones
GnRH, TRH, CRH, GHRH
Enumerate the 4 placental peptide hormones
Leptin, Neuopeptide Y, Inhibin and Activin
Synthesis of Neuropeptide Y occurs in, function of neuropeptide Y
cytotrophoblast, CRH release
Anti-obesity hormone
Leptin
