True about hCG
**Core Concept**
Human chorionic gonadotropin (hCG) is a hormone produced during pregnancy that is essential for maintaining the corpus luteum and supporting embryonic development. hCG is a glycoprotein hormone that stimulates the corpus luteum to produce progesterone, which is crucial for maintaining pregnancy.
**Why the Correct Answer is Right**
hCG is produced by the placenta after implantation of the embryo. It has a structure similar to luteinizing hormone (LH), which allows it to bind to the LH receptor on the corpus luteum. This binding action stimulates the corpus luteum to produce progesterone, which is essential for maintaining the early stages of pregnancy. The production of hCG is regulated by the presence of the embryo and is a critical indicator of normal embryonic development.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because hCG is not produced by the pituitary gland.
**Option B:** Incorrect because hCG is not a hormone produced by the thyroid gland.
**Option C:** Incorrect because hCG is not a hormone that stimulates the release of insulin.
**Clinical Pearl / High-Yield Fact**
It's essential to note that hCG is used as a tumor marker for certain types of cancer, such as choriocarcinoma and germ cell tumors. Abnormal levels of hCG can indicate the presence of these cancers.
**Correct Answer:** D.