Hypothalamic–pituitary–adrenal axis the midbrain that mediate the general adaptation syndrome (GAS). While steroid hormones are produced mainly in vertebrates, the physiological role of the HPA axis and corticosteroids in stress response is so fundamental that analogous systems can be found in invertebrates and monocellular organisms as well. The HPA axis, HPG axis, HPT axis, and the hypothalamic–neurohypophyseal system are the four major neuroendocrine systems through which the hypothalamus and pituitary direct neuroendocrine function. The key elements of the HPA axis are: CRH and vasopressin are released from neurosecretory nerve terminals at the median eminence. CRH is transported to the anterior pituitary through
Pituitary pars intermedia dysfunction Pituitary pars intermedia dysfunction Pituitary pars intermedia dysfunction (PPID), or equine Cushing's disease, is an endocrine disease affecting the pituitary gland of horses. It is most commonly seen in older animals, and is classically associated with the formation of a long, wavy coat (hirsutism) and chronic laminitis. Unlike the human and canine forms of Cushing's disease, which most commonly affect the pars distalis region of the pituitary gland, equine Cushing's disease is a result of hyperplasia or adenoma formation in the pars intermedia. This adenoma then secretes excessive amounts of normal products, leading to clinical signs. The pituitary gland consists