Growth hormone
Category: Hormones · Last updated
Growth hormone (GH), also called somatotropin, is a 191-amino-acid peptide hormone secreted by somatotroph cells of the anterior pituitary gland. It binds the growth hormone receptor (GHR), a class I cytokine receptor, on hepatocytes and peripheral tissues. The dominant downstream readout is hepatic production of insulin-like growth factor 1 (IGF-1).
Secretion
GH is released in pulses, with the largest pulse occurring during the first hours of slow-wave sleep. Two principal regulators control the pituitary somatotrophs:
- GHRH (Growth Hormone-Releasing Hormone, 44 amino acids) · stimulates GH release via the GHRH_receptor.
- Somatostatin · inhibits GH release.
- Ghrelin · the "second" GH secretagogue, binds GHS-R1a (the Ghrelin_receptor) and amplifies the GHRH-mediated pulse.
Relevance to research peptides
Several peptides in this catalog are studied for activity at the GH-axis:
- CJC-1295 · GHRH(1-29) analog, GHRH-receptor agonist
- Tesamorelin · GHRH(1-44) analog, FDA-approved as Egrifta® for HIV-associated lipodystrophy
- Ipamorelin · selective ghrelin-receptor agonist
- GHRP-6 · older non-selective ghrelin-receptor agonist
- Hexarelin · older non-selective ghrelin-receptor agonist