Gonadotrophine

The gonadotrophines or gonadotropines are glycoproteic Hormones complex acting on the functions of the Gonades (ovary S and Testicule S). Two of these hormones are secreted at all the vertebrate ones by the former Hypophyse:

the Hormone lutéinisante (LH)
the folliculo-stimulative Hormone (FSH)

At only two groups of mammals, équidés Primates and , there exists also a chorionic gonadotrophine:

the human Gonadotrophine chorionic (hCG) secreted in very great quantity as of the 8th day during gestation in the expectant mother.
the equine Gonadotrophine chorionic (eCG) in the past called PMSG (Pregnant Pond Gonadotropin Serum) secreted at the Mare gestante starting from the 36e day of gestation.

Structure

The gonadotropines are made of two glycoproteic sub-units alpha and beta associated in a not-covalent way (quaternary structure). This association is essential so that these hormones are active. The sub-unit alpha is, at a given species, commune with the LH, the FSH, the TSH (thyréo-stimulative Hormone) thus, so present, that with the chorionic gonadotrophine. Each sub-unit beta is, on the other hand, specific of each glycoproteic hormone.

Functions

The gonadotropines play a central role in the regulation of the reproduction at all the vertebrate ones. They act on the somatic Cellules of the Gonade S which have receiving S membrane specific for them. By their actions on these somatic cells, the gonadotropines control so much the Gamétogénèse in the males (Spermatogénèse) that in the females (Folliculogénèse). The synthesis and the release of these gonadotrophines FSH and LH must with the Neurohormone gonadolibérine or GnRH, by hypophyseal cells in a pulsatory way.

Simple: Gonadotropin

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