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 replacement; in this case, blood levels of cortisol are determined at 9:00 AM (as cortisol levels vary over the day). A level below 550 nmol/l indicates a need for replacement. The decision on whether to surgically decompress the pituitary gland is complex and mainly dependent on the severity of visual loss and visual field defects. If visual acuity is severely reduced, there are large or worsening visual field defects, or the level of consciousness falls consistently, professional guidelines recommend that surgery is performed. Most commonly, operations on the pituitary gland are performed through transsphenoidal surgery. In this procedure, surgical instruments