Hypophysis Health Dictionary

Also known as the pituitary body and the hypophysis, this is an ovoid structure, weighing around 0·5 gram in the adult. It is attached to the base of the BRAIN, and lies in the depression in the base of the skull known as the sella turcica. The anterior part is called the adenohypophysis and the posterior part the neurohy-P pophysis. The gland is connected to the HYPOTHALAMUS of the brain by a stalk known as the hypophyseal or pituitary stalk.

The pituitary gland is the most important ductless, or endocrine, gland in the body. (See

ENDOCRINE GLANDS.) It exerts overall control of the endocrine system through the media of a series of hormones which it produces. The adenohypophysis produces trophic hormones (that is, they work by stimulating or inhibiting other endocrine glands) and have therefore been given names ending with ‘trophic’ or ‘trophin’. The thyrotrophic hormone, or thyroid-stimulating hormone (TSH), exerts a powerful in?uence over the activity of the THYROID GLAND. The ADRENOCORTICOTROPHIC HORMONE (ACTH) stimulates the cortex of the adrenal glands. GROWTH HORMONE, also known as somatotrophin (SMH), controls the growth of the body. There are also two gonadotrophic hormones which play a vital part in the control of the gonads: these are the follicle-stimulating hormone (FSH), and the luteinising hormone (LH) which is also known as the interstitial-cell-stimulating hormone (ICSH) – see GONADOTROPHINS. The lactogenic hormone, also known as prolactin, mammotrophin and luteotrophin, induces lactation.

The neurohypophysis produces two hormones. One is oxytocin, which is widely used because of its stimulating e?ect on contraction of the UTERUS. The other is VASOPRESSIN, or the antidiuretic hormone (ADH), which acts on the renal tubules and the collecting tubules (see KIDNEYS) to increase the amount of water that they normally absorb.... pituitary gland

n. the surgical removal or destruction of the pituitary gland (hypophysis) in the brain. The operation may be conducted by opening the skull or by the insertion of special needles that produce a very low temperature (see cryosurgery). Radiotherapy (e.g. by insertion of needles of *yttrium-90) can also be used to destroy parts of the pituitary.... hypophysectomy

n. a rare condition of inflammation of the *pituitary gland (hypophysis). The main cause is an infiltration by lymphocytes, most commonly during or just after pregnancy. This usually presents as a mass lesion of the pituitary with visual-field loss and headache or with anterior *hypopituitarism, which may be total or just involve particular hormone systems. Around 50% of cases are associated with other autoimmune endocrine diseases, and antipituitary antibodies have been identified.... hypophysitis