With hypopituitarism, “hypo” means under and “pituitarism” refers to the pituitary gland which normally secretes various endocrine hormones.
So hypopituitarism is the underproduction of hormones released by the pituitary gland, and the symptoms depend on which hormones are actually undersecreted.
If all of the pituitary hormones are affected, it’s called panhypopituitarism.
The pituitary is a pea-sized gland, hanging by a stalk from the base of the brain.
It sits just behind the eyes near the optic chiasm, which is where the optic nerves cross and the gland rests in a very small depression of the skull known as the sella turcica.
The pituitary gland produces and secretes hormones when it receives signals from another part of the brain called the hypothalamus.
Together, they form the hypothalamic-pituitary axis which regulates the release of all the major endocrine hormones.
The pituitary itself has two distinct parts: the anterior pituitary and the posterior pituitary.
The anterior pituitary, which is the front of the pituitary gland, contains a few different types of cells, each of which secretes a different hormone.
The largest group of cells are the somatotropes which secrete growth hormone, which goes on to promote tissue and organ growth.
The second largest cell group are the corticotrophs which secrete adrenocorticotropic hormone, or ACTH, which stimulates the adrenal glands to secrete cortisol, a hormone that controls the stress response, blood pressure, and metabolic regulation.