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
Combined rapid anterior pituitary evaluation panel Combined rapid anterior pituitary evaluation panel A triple bolus test or a dynamic pituitary function test is a medical diagnostic procedure used to assess a patient's pituitary function. A triple bolus test is usually ordered and interpreted by endocrinologists. In rare cases, it has been associated with pituitary apoplexy. Three hormones (usually synthetic analogues) are injected as a bolus into the patient's vein to stimulate the anterior pituitary gland: The gland's response is assessed by measuring the rise in cortisol and growth hormone (GH) in response to the hypoglycaemia caused by insulin, rises in prolactin and thyroid-stimulating hormone (TSH) caused