HCG

HCG

Gonadotropin

Overview

Human chorionic gonadotropin (hCG) is a hormone for the maternal recognition of pregnancy produced by trophoblast cells that are surrounding a growing embryo (syncytiotrophoblast initially), which eventually forms the placenta after implantation. The presence of hCG is detected in some pregnancy tests (HCG pregnancy strip tests). Some cancerous tumors produce this hormone; therefore, elevated levels measured when the patient is not pregnant may lead to a diagnosis of cancer and, if high enough, of paraneoplastic syndromes. It is unknown however whether this production is a contributing cause or an effect of carcinogenesis. The pituitary analogue of hCG, luteinizing hormone (LH), is produced in the pituitary gland of males and females of all ages.

Beta-hCG is initially secreted by the syncytiotrophoblast.

Source: English Wikipedia, "Human chorionic gonadotropin".

Mechanism of Action

Human chorionic gonadotropin interacts with the LHCG receptor of the ovary and promotes the maintenance of the corpus luteum for the maternal recognition of pregnancy at the beginning of pregnancy. This allows the corpus luteum to secrete the hormone progesterone during the first trimester. Progesterone enriches the uterus with a thick lining of blood vessels and capillaries so that it can sustain the growing fetus.

It has been hypothesized that hCG may be a placental link for the development of local maternal immunotolerance. For example, hCG-treated endometrial cells induce an increase in T cell apoptosis (dissolution of T cells). These results suggest that hCG may be a link in the development of peritrophoblastic immune tolerance, and may facilitate the trophoblast invasion, which is known to expedite fetal development in the endometrium. It has also been suggested that hCG levels are linked to the severity of morning sickness or hyperemesis gravidarum in pregnant women.

Because of its similarity to LH, hCG can also be used clinically to induce ovulation in the ovaries as well as testosterone production in the testes. As the most abundant biological source is in women who are presently pregnant, some organizations collect urine from pregnant women to extract hCG for use in fertility treatment.

Human chorionic gonadotropin also plays a role in cellular differentiation/proliferation and may activate apoptosis.

^ "Stages of Fetal Development - First Trimester | Department of Health | State of Louisiana". ldh.la.gov. Retrieved 2021-02-16.

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