Gonadotrophin Releasing Hormone (GnRH) is a hormone that is responsible for the stimulation of specific cells called gonadotrophs in the pituitary gland. This stimulation results in the production of two important hormones called LH (luteinising hormone) and FSH (follicular stimulating hormone) from the pituitary. GnRH is of great importance in the menstrual cycle. One of the most important features of GnRH release is the fact that its release occurs in a pulsatile fashion. At the start of puberty there is a marked increase in the frequency and amplitude of GnRH release.