Hypothalamic–pituitary–gonadal 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 a single system. The HPG axis plays a critical part in the development and regulation of a number of the body's systems, such as the reproductive and immune systems. Fluctuations in this axis cause changes in the hormones produced by each gland and have various local and systemic effects on the body. The axis
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