Growth hormone (GH) [Neurosurgery Wiki]

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====== Growth hormone (GH) ======

[[GH]] is produced by the [[pituitary gland]] and plays a crucial role in [[growth]],[[ metabolism]], and various physiological processes, cell [[reproduction]], and [[cell]] [[regeneration]] in humans and other animals. It is thus important in human development. It is a type of mitogen that is specific only to certain kinds of cells. 

Growth hormone is a 191-amino acid, single-chain polypeptide that is synthesized, stored, and secreted by somatotropic cells within the lateral wings of the [[anterior pituitary]].

GH is a stress hormone that raises the concentration of glucose and free fatty acids.

Growth [[hormone]] (GH), which has been extracted from the [[pituitary gland]] since early times, has become easily available by the advance of genetic engineering.

see [[Long acting growth hormone]].



GH normally has pulsatile secretion (≈ 5–10 pulses/ 24 hours, primarily at night, up to 30 mcg/L), levels may be undetectable (< 0.2 mcg/L) by standard assays between pulses.
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There is uncertainty about the appropriate cut-off for the diagnosis of [[growth hormone deficiency]] and little data about the yield of significant abnormal findings in patients with peak [[growth hormone]] ([[GH]]) of 7-10 ng/mL. 
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IGF-1 is the primary test for excess [[growth hormone]] (GH); direct measurement of GH is unreliable

Insulin-like growth factor-1 ([[IGF-1]]) (formerly known as somatomedin-C) is the protein secreted primarily by the [[liver]] in response to GH that is responsible for most of GH’s systemic effects. 
GH also acts directly on epiphyseal endplates of long bone to stimulate chondrocyte proliferation.
Control: GH is under dual hypothalamic control via the hypophysial portal system. GH-releasing hormone ([[GHRH]]) from the [[arcuate nucleus]] stimulates the pituitary secretion and synthesis of GH and induces GH gene transcription. [[Somatostatin]] from the [[periventricular nucleus]] suppresses GH release only, and has no effect on synthesis. GH release is also stimulated by [[ghrelin]], a peptide synthesized primarily in the GI tract in response to certain nutrients (may act partially or totally via hypothalamic GHRH).
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===== Growth hormone related pathology =====

see [[Growth hormone related pathology]].


===== Growth hormone replacement therapy =====

[[Growth hormone replacement therapy]].