Also known as the growth-hormone-releaseinhibiting factor, this is a hormone secreted by the HYPOTHALAMUS and some non-nervous tissues (including the gastrointestinal tract and pancreas). It stops the pituitary-releasing somatotrophin – GROWTH HORMONE. Somatostatin and growth-hormone-releasing hormone are controlled by complicated neural mechanisms linked to exercise, sleep patterns, stress, NEUROTRANSMITTERS and blood GLUCOSE.... somatostatin
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. abnormal growth causing excessive height, most commonly due to oversecretion during childhood of *growth hormone (somatotrophin) by the pituitary gland. In eunuchoid gigantism the tall stature is due to delayed puberty, which results in continued growth of the long bones before their growing ends (epiphyses) fuse. See also Sotos syndrome.... gigantism
(GH, somatotrophin) a hormone, synthesized and stored in the anterior pituitary gland, that promotes growth of the long bones in the limbs and increases protein synthesis (via *somatomedin). Its release is controlled by the opposing actions of growth-hormone releasing hormone and *somatostatin. Excessive production of growth hormone results in *gigantism before puberty and *acromegaly in adults. Lack of growth hormone in children causes *dwarfism. Synthetic human growth hormone (somatotropin) is used to treat a variety of conditions of growth-hormone deficiency. Pegvisomant is an analogue of human growth hormone that blocks GH receptors; it may be used to treat acromegaly.... growth hormone
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