Growth-hormone-releasing hormone

Growth-hormone-releasing hormone (GHRH), also known as somatocrinin, is a hormone that stimulates the release of growth hormone (GH) from the anterior pituitary gland. It is a key player in the endocrine system, specifically in the regulation of growth and development.

Structure

GHRH is a 44-amino acid peptide hormone produced in the hypothalamus. The active form of GHRH is a 1-29 fragment (GHRH(1-29)) which represents the first 29 amino acids of the full-length hormone.

Function

GHRH stimulates the synthesis and secretion of GH from the anterior pituitary gland. It does this by binding to the GHRH-receptor, a G-protein coupled receptor, on the surface of pituitary somatotroph cells. This binding triggers a cascade of intracellular events that ultimately leads to the release of GH into the bloodstream.

Regulation

The release of GHRH is regulated by various factors. These include neurotransmitters such as serotonin, dopamine, and norepinephrine, as well as hormones like somatostatin and ghrelin. In addition, factors such as sleep, exercise, and nutrition can also influence the release of GHRH.

Clinical significance

Abnormalities in GHRH function can lead to various disorders. For example, overproduction of GHRH can lead to acromegaly, a condition characterized by excessive growth. On the other hand, underproduction of GHRH can result in growth hormone deficiency, which can lead to short stature in children and a variety of metabolic abnormalities in adults.

See also

• Growth hormone
• Hypothalamus
• Anterior pituitary
• Endocrine system