Human Chorionic Gonadotropin (HCG)

Edited by Eugenio Ciuccetti, Obstetrician

What is that

Human Chorionic Gonadotropin is the so-called pregnancy hormone. As the name suggests, it is a hormone belonging to the Gonadotropin family: such as LH (luteinizing hormone) and FSH (follicle-stimulating hormone). All three act on the female gonads, or the ovaries.

Synthesis and secretion

However, while LH and FSH are produced by the adenohypophysis (ie the anterior pituitary), the Human Chorionic Gonadotropin is a liberated glycoprotein, during pregnancy, from the trophoblast, therefore from the placenta. Actually the HCG starts to be produced already by the blastocyst, even before the same implant takes place, and its presence in the maternal blood can be detected about a week after the ovulation that will have given rise to conception.

We recall, in this regard, that since the first days of pregnancy the fertilized egg undergoes a rapid process of cellular multiplication, passing from the morula stage to that of balstocysts. On the other hand, nesting in utero occurs about eight days after conception itself.

From this moment on, the amount of Human Chorionic Gonadotropin present in the mother will tend to increase very consistently and continuously until the second / third month of pregnancy, to then decrease and finally stabilize (around the sixteenth week of gestation) until the time of childbirth. It should be noted that the decrease in HCG in maternal blood occurs simultaneously with the increase in production - always at the placental level - of progesterone.

Functions

Human Chorionic Gonadotropin plays a key role - in the early stages of pregnancy - in keeping the corpus luteum, formed following ovulation, active. The latter in fact derives from the follicle that will have freed the subsequently fertilized egg. This preservation of the corpus luteum is fundamental at the beginning of gestation: it is he who produces the progesterone necessary for the initial development of the decidua. This function is then exhausted over the course of the weeks, when the placenta itself will ensure sufficient release of this hormone.

Human Chorionic Gonadotropin has traditionally been used to carry out the same pregnancy tests. First with biological methods such as Galli-Mainini (on experimental animals) and subsequently with the various radio-immunological and immuno-fluorimetric techniques that allow a better dosage of HCG and its alpha and beta fractions. Dosage that is also useful in monitoring some pathological conditions, such as the threat of abortion or ectopic pregnancies. The dosage of Human Chorionic Gonadotropin can be performed both on urine and blood.

Use in sports

In the sports field, chorionic gonadotropin is used to stimulate testosterone production by Leydig's testicular cells, mimicking the natural action of the LH hormone. The use of this hormone - considered a dangerously health-giving doping practice - is mainly done to reactivate the endogenous production of testosterone following the cessation of anabolic steroid abuse.