This is a working overview of growth hormone, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-12-25 and is reviewed periodically as new material appears.
The native hormone is produced in the hypothalamus and acts on the anterior pituitary. Binding of GHRH to its receptor stimulates synthesis and release of growth hormone into circulation. Because the analogue retains the receptor-binding region of the parent sequence, it engages the same receptor and triggers the same downstream signaling. The result is increased growth hormone secretion from pituitary cells, which in turn influences hepatic production of insulin-like growth factor 1. This axis is the basis for the compound's measured biological effects.
Interest in this peptide developed because native GHRH has a short circulating lifetime. The N-terminal modification slows cleavage by dipeptidyl peptidase IV, an enzyme that removes the first two residues of many peptides and terminates their activity. Slower degradation means a longer window of receptor stimulation per administration. This design logic parallels other modified peptide hormones, where a small chemical change at a vulnerable site yields a more durable molecule without altering the core mechanism of action.
Tesamorelin is a synthetic peptide analog of growth hormone-releasing hormone, composed of 44 amino acids. It was designed to retain the biological activity of the native hormone while resisting rapid enzymatic degradation. The compound is classified as a growth hormone secretagogue and belongs to the broader family of hypothalamic releasing factors. In research and clinical settings, it is studied for its ability to stimulate pituitary growth hormone release. Its structure includes a modification at the N-terminus that contributes to an extended half-life relative to native growth hormone-releasing hormone.
Tesamorelin binds to growth hormone-releasing hormone receptors on the surface of pituitary somatotroph cells. This binding activates adenylate cyclase, raising intracellular cyclic AMP levels and triggering the release of growth hormone into circulation. The elevated growth hormone then stimulates hepatic production of insulin-like growth factor 1. Because the effect is mediated through the endogenous axis, secretion remains subject to feedback regulation. This distinguishes it from direct growth hormone administration, which bypasses pituitary control entirely.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C221H366N72O67S | Reflects a 44-residue peptide with one N-terminal modification |
| Approximate molecular weight | 5136 Da | Sequence length and single acyl group determine the mass |
| Appearance | White to off-white lyophilized powder | Typical form of a purified synthetic peptide |
| Solubility class | Soluble in water and aqueous buffer | Peptide backbone favors aqueous dissolution |
| Common synonyms | GHRH(1-44) analogue; Egrifta | Descriptive name and approved brand name |
In fungi, AAA is reduced to α‑aminoadipate-semialdehyde via AAA reductase (E.C 1.2.1.95) in a unique process involving both adenylation and reduction that is activated by a phosphopantetheinyl transferase (E.C 2.7.8.7). Once the semialdehyde is formed, saccharopine reductase (E.C 1.5.1.10) catalyses a condensation reaction with glutamate and NAD(P)H, as a proton donor, and the imine is reduced to produce the penultimate product, saccharopine. The final step of the pathway in fungi involves the saccharopine dehydrogenase (SDH) (E.C 1.5.1.8) catalysed oxidative deamination of saccharopine, resulting in L-lysine. In a variant AAA pathway found in some prokaryotes, AAA is first converted to N‑acetyl-α-aminoadipate, which is phosphorylated and then reductively dephosphorylated to the ε-aldehyde. The aldehyde is then transaminated to N‑acetyllysine, which is deacetylated to give L-lysine. However, the enzymes involved in this variant pathway need further validation.
== History == Buspirone was first synthesized by a team at Mead Johnson in 1968 but was not patented until 1980. It was initially developed as an antipsychotic acting on the D2 receptor but was found to be ineffective in the treatment of psychosis; it was then used as an anxiolytic. In 1986, Bristol-Myers Squibb gained FDA approval for buspirone in the treatment of GAD. The patent expired in 2001, and buspirone is available as a generic drug.
=== A Loner (2020–2023) === The joint concert of Hangman's Chair and Regarde Les Hommes Tomber was due to be repeated at the Roadburn Festival 2020, but the performance ultimately did not take place. Chanut stated that Hangman's Chair recorded the album A Loner from December 2020 to January 2021, or, according to Thépegnier, until February 2021, with a view to an October release, but concert cancellations delayed it. Thépegnier indicated that the band's relationship with their former labels, Bones Brigade and Music Fear Satan, had always gone well. They had high expectations for Spinefarm Records, but ultimately, things did not go as planned. "Communication with Spinefarm has become very complicated", said Thépegnier. To amicably terminate their contract, Hangman's Chair initiated negotiations through their new manager. They were approached by the German and French offices of Nuclear Blast Records. The deal had accelerated after the opening of the French office because the band had already been in contact with the German office since This Is Not Supposed To Be Positive. Following their signing with Nuclear Blast Records, they released a new single titled "Cold & Distant" on 21 May 2021, accompanied by its music video featuring French actress Béatrice Dalle. Perturbator asked Hangman's Chair to collaborate on his song "God Says", from his 2021 album, Lustful Sacraments. Due to the coronavirus pandemic, the annual Hellfest could not take place, but a 15-minute live session from the band was made available on the festival's website in June 2021.
Sources: en.wikipedia.org
Bacterial and mitochondrial N-formyl peptides such as FMLP – pro-inflammatory (though possibly less physiologically significant than lipid-derived ligands); Hp(2–20), from Helicobacter pylori – pro-inflammatory; HIV-1-derived peptides: T21/DP107 and N36 (from gp41), F peptide (from gp120), and V3 peptide (from the MN strain) – unknown effects; CCL23β (amino acids 22–137), a splice variant of CCL23, and SHAAGtide, a proteolytic product – pro-inflammatory; Annexin A1-derived peptides (Ac2–26 and Ac9–25) – dose-dependent; anti-inflammatory at low concentrations, pro-inflammatory at high concentrations; Amyloid β(1–42) and PrP(106–126) (from prion protein) – pro-inflammatory, suggesting roles in Alzheimer's disease, Parkinson's disease, Huntington's disease, and prion diseases such as Creutzfeldt–Jakob disease and Kuru; Humanin, a neuroprotective peptide – anti-inflammatory, counteracting amyloid-induced inflammation; Cleaved fragments of UPARAP (uPAR): D2D3(88–274) and uPAR(84–95) – pro-inflammatory; Antimicrobial peptides: LL-37 and CRAMP (human/rat cathelicidins), Pleurocidins (from fish), and Temporin A (frog-derived) – pro-inflammatory; Pituitary adenylate cyclase-activating polypeptide 27 – pro-inflammatory; Long-chain ceramides (C14–C20) – bind FPR2 in beige and brown adipocytes to inhibit thermogenesis.
=== Examples === In older literature, paralogous genes are often misleadingly called isoforms, or isozymes in the case of enzymes. For example, the 5' AMP-activated protein kinase (AMPK), an enzyme, which performs different roles in human cells, has 3 subunits:
The modifications covered in this diagram have to do with carbon skeleton modifications of the original fentanyl molecular structure. These are organized into methyl acetate additions, which are most known for the fentanyl -> carfentanil conversion. Many analogues of great potency, such as ohmfentanyl and lofentanyl possess methyl acetate groups added to the 4-carbon (of the piperidine ring, in the para- position relative to the annular nitrogen). The methyl acetate is added here from the α-carbon of the acetate moiety as it is with ohm- and lofentanyl. The 4-carbon is not a chiral center in carfetnanil because of a lack of piperidinyl substituents, but this same carbon is a chiral center in both ohm- and lofentanyl because both of those analogues have piperidinyl substituents. The second group are organized into methyl additions, which are known for the fentanyl analogues such as α-methylfentanyl and cis-3-methylfentanyl. These analogues can possess a wide variety of modified pharmacological properties, including increased and decreased potency (receptor binding efficiency), increased or decreased half-life (metabolic binding efficiency) or other side effects on human physiology. Other substituents such as hydroxy, chloro, fluoro, and a wide variety of alkyl groups, are also substituted in place of these methylations to produce psychoactive analogues of fentanyl, but because they often use the same skeletal naming conventions as the simple methyl analogues, we did not reproduce them all in the image here.
Sources: en.wikipedia.org
It shares the 44-residue sequence of human GHRH but carries an added trans-3-hexenoyl group at its N-terminus. That addition does not occur in the natural hormone and serves mainly to resist enzymatic breakdown. The receptor target and signaling pathway remain the same.
It binds the growth hormone-releasing hormone receptor on anterior pituitary cells. Activation of that receptor promotes synthesis and release of growth hormone. The effect propagates through the growth hormone and insulin-like growth factor 1 axis.
Native GHRH is cleared quickly by peptidases, which limits how long it can stimulate its receptor. The added group hinders one of the primary cleavage enzymes. The practical consequence is a longer period of receptor activity per dose.
It is a synthetic analog of growth hormone-releasing hormone, a hypothalamic peptide. It functions as a growth hormone secretagogue acting at pituitary receptors. The classification separates it from direct growth hormone products.