HCG is produced by -

Ans. is 'b' i.e., Placenta o In all mammals, the corpus iuteum in the ovary at the time of fertilization fails to regress and instead enlarges in response to stimulation by gonadotropic hormones secreted by the placenta,o The placental gonadotropin in humans is called human chorionic gonadotropin (hCG). hCG secretion decreases after an initial marked rise, but estrogen and progesterone secretion increase until just before parturition,o hCG is a glycoprotein produced by the syncytiotrophoblast. hCG-a is identical to the a subunit of LH, FSH, and TSH.o The molecular weight of hCG-a is 18.000, and that of hCG-b is 28,000.o hCG is primarily luteinizing and luteotropic and has little FSH activity.o It can be measured by radioimmunoassay and detected in the blood as early as 6 days after conception.o Its presence in the urine in early pregnancy is the basis of the various laboratory tests for pregnancy, and it can sometimes be detected in the urine as early as 14 days after conception,o It appears to act on the same receptor as LH.