Hypothalamic–pituitary–gonadal axis in which the hypothalamus and pituitary direct neuroendocrine function. The hypothalamus is located in the brain and secretes GnRH. GnRH travels down the anterior portion of the pituitary via the hypophyseal portal system and binds to receptors on the secretory cells of the adenohypophysis. In response to GnRH stimulation these cells produce LH and FSH, which travel into the blood stream. These two hormones play an important role in communicating to the gonads. In females FSH and LH act primarily to activate the ovaries to produce estrogen and inhibin and to regulate the menstrual cycle and ovarian cycle. Estrogen forms
Pituitary apoplexy or nonsecretory tumors, which do not produce excessive amounts of hormones; this might explain why the tumor has often gone undetected prior to an episode of apoplexy. The first case description of pituitary apoplexy has been attributed to the American neurologist Pearce Bailey in 1898. This was followed in 1905 by a further report from the German physician Bleibtreu. Surgery for pituitary apoplexy was described in 1925. Before the introduction of steroid replacement, the mortality from pituitary apoplexy approximated 50%. The name of the condition was coined in 1950 in a case series by physicians from Boston City Hospital and