Placental Hormones

Question 1

Referred as the pregnancy hormone.

Answer 1

Human Chorionic Gonadotropin (HCG)

Question 2

HCG is almost exclusively produced by the _______.

Answer 2

Syncitiotrophoblast

Question 3

Normal amount of HCG in men and non-pregnant women.

Answer 3

0-5 mIU/mL

Question 4

What is being detected in the urine to indicate pregnancy?

Answer 4

HCG

Question 5

Day when the HCG can be detectable in the plasma of a pregnant woman.

Answer 5

7-9 days

Question 6

High level of HCG can be an indication of

Answer 6

○ multiple fetuses (i.e. twin pregnancy)
○ single erythroblastotic fetus
○ H. mole
○ choriocarcinoma
○ a fetus with Down syndrome

Question 7

Low level of HCG can be indicative of

Answer 7

○ ectopic pregnancy

○ spontaneous abortion

Question 8

Where is HnRH produced?

Answer 8

Cytotrophoblast

— which acts on syncytiotrophoblast→ stimulate hCG secretion

Question 9

What is the metabolic clearance of HCG? ml/l per min/day

Answer 9

3ml/min or 4 liters of plasma/day

Question 10

Reviewer:

Enumerate the biological functions of HCG:

Answer 10

1. Rescue and maintenance of corpus luteum in
   early pregnancy→ continued progesterone
   production
2. Downregulation of hCG/LH receptors in corpus luteum when trophoblasts produce sufficient progesterone for pregnancy maintenance
3. Stimulates fetal testicular testosterone
   secretion and promote male sexual differentiation
4. Stimulates the maternal thyroid via LH/hCG receptors and TSH receptors.
5. Promotes relaxin secretion by the corpus
   luteum
6. Promote uterine vascular vasodilation and
   myometrial smooth muscle relaxation
7. Induces ovulation in the FSH primed ovaries of
   non-pregnant women

Question 11

This relaxes uterus to avoid hyperactivity during pregnancy.

Answer 11

Relaxin

Question 12

HPL is alson known as

Answer 12

chorionic growth hormone,

chorionic somatomammotropin

Question 13

At 5-10 days after fertilization, HPL can be seen in the

Answer 13

placenta

Question 14

During 5th week of pregnancy, HPL can be seen in

Answer 14

serum of pregnant women

Question 15

It functions as a fail-safe mechanism to ensure
nutrient supply to fetus in times of maternal
starvation

Answer 15

HPL

Question 16

Acetate and cholesterol is converted to androstenedione in the

Answer 16

Theca cells

Question 17

Adrostenedione is converted to estrone then to estradiol 17B in the

Answer 17

Granulosa cell

Question 18

Precursors for Estrogen Synthesis:

Answer 18

○ Maternal plasma
dehydroepiandrosterone sulfate
(DHEAS)
○ Liver: 16-hydroxy
dehydroepiandrosterone
○ Fetal DHEAS

Question 19

Non-pregnant women ratio of estradiol and estrone to estriol vs during pregnance

Answer 19

Non-pregnant - 1

During pregnancy - 10

Question 20

What is the principal precursor for fetal steroidogenesis?

Answer 20

Fetal plasma cholesterol

Sources:
20% - maternal transfer
80% - de novo synthesis by fetal liver

Question 21

This fetal induced modification of estrogen production is due to the inability to convert dehydroepiandrosterone to estradiol.

Answer 21

Placental aromatase deficiency

Question 22

Disease caused by diminished availability of C- 19 steroid precursor because of the absence of adrenal cortex

Answer 22

Fetal Anencephaly

Question 23

What happens with the placental estrogen on fetal death or ligation of the umbilical cord?

Answer 23

Marked decrease in placental estrogens -

precursor of placental estrogen is lost

Question 24

T/F

Estriol is not used anymore to assess the fetal well-being

Answer 24

True

Question 25

Where does biosynthesis of progesterone happen?

Answer 25

syncytiotrophoblast

Question 26

What is the largest organ of the fetus?

Answer 26

Fetal adrenal gland

Question 27

Conversion of cholesterol to pregnenolone occurs in?

Answer 27

Mitochondria

Question 28

Pregnenolone is converted to progesterone in?

Answer 28

Microsome

Question 29

ACTH is derived from

Answer 29

POMC - propiomenalonocrtion