Gonadotropin-releasing hormone

Gonadotropin-releasing hormone (GnRH), or Luteinizing-hormone-releasing hormone (LHRH), is a hormone synthesized and released from neurons in the hypothalamus.
GnRH occurs in all vertebrates. This single hormone controls all the complex processes which prepare the male and female for successful reproduction.
GnRH releases follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary. 
GnRH activity is very low during childhood, and is activated at puberty or adolescence. During the reproductive years, it is critical for successful reproductive function as controlled by feedback loops. However, once a pregnancy is established, GnRH activity is not required.