Reproductive system physiologyPlacenta

ByKhorrami Ph.D.

http://khorrami1962.spaces.live.com

khorrami4@yahoo.com

Estrogens

Estrone (E1) Estradiol (E2) Estriol (E3) Estetrol (E4)

Estrogen

100mg/day before pregnancy 300mg/day in late pregnancy 85-90% is related to estriol(E3) or its

conjugate

Fetoplacental-maternal unit

Liver Adrenal

fetus

placenta

Mother

DHA-S

acetate

DHA

E1 E2

DHA-S

16-a-DHA-S

16-a-DHA

E3

E3-G

urine

Isomerase

sulfatase

E4

E4: Estetrol

Progesterone At term 250mg/day Excreted as Pregnandiol

End of first trimester:10mg/day At term: 40mg/day

Maternal cholesterol In syncytiotrophoblast:

preg…..progesteron Most passes to fetal circulation

Fetal adrenal……corticosteroid sulphate Remainder to maternal circulation

HCG Found in urine of pregnant women

(1927) Detectable in maternal plasma 7-10

days after implantation Doubling each 48hrs Peak at 8-10th week

Synthesized by: More by syncytiotrophoblast Less by cytotrophoblast

HCG

a subunit: 92 AA common with LH

by single gene (ch.6) In cyto and syncytiotrophoblast cells

b subunit: 134 AA

By 7 genes ( ch.19) In cytotrophoblast cells

Placenta

Lack of MHC-I and MHC-II in trophoblast cells

Presence of Fas-ligand in placenta Apoptosis of activated T cells