GHRH Human

Growth Hormone-Releasing Hormone (GHRH), also known as somatocrinin or somatorelin, is a peptide hormone that plays a crucial role in regulating the secretion of growth hormone (GH) from the anterior pituitary gland. GHRH is produced in the hypothalamus and is essential for normal growth, metabolism, and overall body structure.

GHRH was first identified in the human hypothalamus between 18 and 29 weeks of gestation, which corresponds to the onset of growth hormone production in fetuses . The hormone is known by several names, including somatocrinin, somatoliberin, and growth hormone-releasing factor (GHRF) .

GHRH is a 44-amino acid peptide hormone . It is released from neurosecretory nerve terminals in the hypothalamus and carried by the hypothalamo-hypophyseal portal system to the anterior pituitary gland. Here, it binds to the growth hormone-releasing hormone receptor (GHRHR) on somatotroph cells, stimulating the secretion of growth hormone .

The binding of GHRH to its receptor activates the cAMP-dependent pathway, leading to increased intracellular cyclic adenosine monophosphate (cAMP) levels . This activation results in the phosphorylation of the transcription factor cAMP response element-binding protein (CREB), which enhances the transcription of the GH gene . Additionally, GHRH promotes slow-wave sleep directly .

The secretion of GHRH is regulated by various factors, including somatostatin, a hormone that inhibits GH release . Ghrelin, known as the “hunger hormone,” also regulates GHRH and GH release . Physiological conditions such as sleep, stress, exercise, and food intake influence the release of GHRH and somatostatin .

Excessive production of GHRH can lead to conditions such as acromegaly, characterized by the enlargement of hands, feet, and facial features . Conversely, insufficient GHRH production can result in growth hormone deficiency, affecting normal growth and metabolism .