Saturday, 4 April 2015

Hcg

10 Question: Regarding HCG true is all except (PGI) Options:
(1 ) A glycoprotein
(2 ) Has 2 subunits
(3 ) Secreted by trophoblast
(4 ) Alpha subunit is specific✅


HCG :
1. HCG is secreted by Trophoblast cells
2. It is a glycoprotein with high Sialic acid concentration
3. Synthesized by syncytiotrophoblast
4. Has two subunits –
a) Alpha sub-unit – similar biologically to LH, FSH, TSH
b) Beta Sub-unit – unique to HCG
5. Similar structurally to FSH
6. Molecular weight of Alpha – 18000;
Beta – 28000
7. Half life of Beta HCG – 24 hrs
8. HCG is primarily Lutinizing and Leutrotrophic and has little FSH cativity
9. Doubling time of HCG – 1.4 – 2 days
10. Detected in Maternal serum as early as 8 days by immunoassay
11. Level is 100 IU/L
12. Maximum levels of 10,0000IU/L at 8 – 10 weeks (70days)
13. Falls till 18th weeks and remains at low level of 10,000 till term.
14. High levels seen in – Hydatidiform mole; Multiple pregnancy; Down’s syndrome
15. HCG disappears from circulation by 2 weeks following delivery
Other actions of HCG :
1. Sustains Corpus leuteum
2. Stimulates Leideg cells of male fetus to produce testosterone and there by induces development of male external genitalia
3. Immuno-suppressive action helps in the maintenance of pregnancy
Cinical condition where Beta- HCG levels are low are :
1. Threatened / Spontaneous abortion
2. Ectopic pregnancy
3. Trisomy 18 (Edward syndrome)
Rest in all it is increased ! List for Increased Beta-HCG :
1. Pregnancy
2. Successful therapeutic insemination
3. Hydatidiform mole
4. Choriocarcinoma
5. Multifetal pregnancy
6. Erythroblastotic fetus
7. Down syndrome
8. Ovarian and testicular tumour
9. Certain neoplasm of lung, stomach, and pancreas !

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