Hormones of Pregnancy Flashcards
What is the hormone of pregnancy?
Progesterone
Histotrophe?
Growth of luminal and glandular endometrial epithelium
What is the major source of progesterone in humans, primates, sheep, and horses?
Placenta
Two places progesterone is found.
Placenta, CL
Name 5 species in which the placenta does not take over progesterone production.
Dog, cat, rabbit, goat, alpaca, llama, camel
What are the 6 actions of progesterone?
1) inhibits or delays LH secretion and ovulation
2) acts on endometrium & myometrium growth with estrogen
3) immunomodulatory
4) uterine quiescence
5) inhibits ER formation
6) blocks OT release from post-pituitary, OT action, and OTR formation
Uterine quiescence?
Inhibits myometrium contractions
What can happen to progesterone concentrations during the luteal phase of the cycle?
May increase greatly (humans) or moderately (sheep) or no difference (cow, pig)
What are the four estrogen hormones?
Estrone (E1), estradiol (E2), estriol (E3), estrone sulphate (E1SO4)
What is the correct potency of the estrogen hormones?
E2 > E1 > E3 > E1SO4
When do estrogens typically rise in pregnancy?
Toward the end of pregnancy
What ate the sources of estrogens?
Ovary, placenta, fetus, or all three
What are the 6 actions of estrogens?
1) with P4, stimulate endometrial, myometrial, and mammary gland growth
2) stimulate ER an OTR
3) participate in uterine tract motility
4) behavior
5) cervical mucous
6) uterine motility, transport, parturition
In which species do estrogen levels not change throughout gestation?
Woman
What are the 3 adrenal steroids?
Cortisol, CBG (corticosteroid binding globulin), aldosterone
Function of cortisol?
Increase due to decreased metabolism
Function of CBG?
Production by liver increase due to estrogen
Function of aldosterone?
Increases when changes in adrenal function are not thought to be related to pregnancy maintenance, in general, a pregnant animal survives adrenalectomy better than a non-pregnant animal
What are the 3 anterior pituitary hormones during pregnancy?
Prolactin, LH, FSH
Prolactin?
Increases due to increased TRH which causes prolactin release
LH and FSH?
Decrease due to negative feedback of progesterone
What are the 7 placental hormones?
Human chorionic gonadotropin (hCG), interferon-tau, equine chorionic gonadotropin (eCG), placental lactogen, insulin-like growth factor I and II, alpha-fetoprotein, relaxin
Functions of human chorionic gonadotropin (hCG)?
1) strong LH activity
2) prevents luteal regression
3) steroidogenic to placenta
4) steroidogenic to fetus
5) pregnancy test
Functions of interferon-tau?
1) maternal recognition protein in ruminants
2) type 1 interferon - antiviral
3) stimulates production of IFN-related proteins
4) inhibits OTR and ER formation
What is equine chorionic gonadotropin (eCG) also known as?
Pregnant Mare Serum Gonadotropin (PMSG)
Function of eCG?
1) produced by chorion
2) has LH-like and FSH-like activity
3) causes luteinization of ovarian follicles
4) accessory corpora lutea, a source of P4
5) produced from approx. 40-120 days
In Which hormone do chorionic cells form a thick equatorial girdle around the chorion?
eCG
In which hormone do cells migrate and invade endometrium forming endometrial cup cells?
eCG
Cells secrete eCG causing accessory CL which secretes what?
P4
Which placental hormone is closely related to GH and PRL?
Placental lactogen
How is placental lactogen synthesized? In humans? Bovine?
By trophoblasts
Human: syncytiotrophoblast
Bovine: giant binucleate cells
When is human placental lactogen (PL) detectable?
In the 5th-6th week and plateaus at term with a concentration of 6-8 micrograms/mL
PL production ____ throughout pregnancy with placental growth.
Increases
What are the 4 actions of placental lactogen?
1) affects metabolic changes in mother
2) glucose sparing (causes mobilization of free FA, shifts delivery of glucose to fetus as placenta
3) in other species, PL has lactogenic/luteotrophic and GH-like activity
4) PL is the dis erogenous factor in pregnancy, highest last 4 weeks, causes abnormal glucose tolerance tests
Functions of insulin-like growth factor I and II?
1) mediates some effects of Growth Hormone
2) found in placental tissues and fetal liver
3) influences growth and glucose metabolism
4) often works in concert with other hormones
5) structurally similar to insulin
Functions of alpha-fetoprotein?
1) produced by yolk sac and fetal liver
2) involved in steroid-binding and osmoregulation similar to albumin
3) in female fetus, binds estradiol, blocking its transfer across blood-brain barrier, thereby protecting female brain from defeminization
Which hormone is diagnostic for neural tube defects - spina bifida, anencephaly (absence of all or part of the brain)?
Alpha-fetoprotein
What factors influence fetal growth?
Fetal hormones (thyroid-skeletal and muscular development, insulin (IGF)-increased energy substrate availability and stimulates placental growth, Growth Hormone (IGF)-stimulates fetal growth
Functions of relaxin?
1) separation of pubis by relaxation of pelvic ligaments
2) may influence the ripening or softening of the cervix
3) in pigs - stimulates uterine growth
What are the sources of relaxin?
Pigs, cows: CL
Humans, mates, cats, pigs, rabbit, monkey: placenta
