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 can be applied as a nose spray or taken by mouth. Pituitary apoplexy is rare. Even in people with a known pituitary tumor, only 0.6–10% experience apoplexy; the risk is higher in larger tumors. Based on extrapolations from existing data, one would expect 18 cases of pituitary apoplexy per one million people every year; the actual figure is probably lower. The average age at onset is 50; cases have reported in people between 15 and 90 years old. Men are affected more commonly than women, with a male-to-female ratio of 1.6. The majority of the underlying tumors are "null cell"