Hypothalamic–pituitary–gonadal axis Much of the research is done on animal models, because they mimic so well the control mechanism of humans. It is important to remember humans are the only species to hide their fertile period, but this effect is a difference in the effect of the hormones rather than a difference in the HPG axis. Hypothalamic–pituitary–gonadal axis The hypothalamic–pituitary–gonadal axis (HPG axis) refers to the hypothalamus, pituitary gland, and gonadal glands as if these individual endocrine glands were a single entity. Because these glands often act in concert, physiologists and endocrinologists find it convenient and descriptive to speak of them as
Sheehan's syndrome Sheehan's syndrome Sheehan's syndrome, also known as postpartum pituitary gland necrosis, is hypopituitarism (decreased functioning of the pituitary gland), caused by ischemic necrosis due to blood loss and hypovolemic shock during and after childbirth. The various signs and symptoms in Sheehan's syndrome are caused by damage to the pituitary, thereby causing a decrease in one or more hormones it normally secretes. Since the pituitary controls many glands in the endocrine system, partial or complete loss of a variety of functions may result. Most common initial symptoms of Sheehan's syndrome are agalactorrhea (absence of lactation) and/or difficulties with lactation. Many women