If you have been reading about GHRH receptor and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-09-12. Numbers and descriptions here follow the published literature rather than marketing material.
CJC-1295 is a synthetic analogue of growth hormone-releasing hormone, built on the 29-amino-acid GHRH(1-29) fragment. Four substitutions distinguish it from the natural sequence: D-alanine at position 2, glutamine at position 8, alanine at position 15, and leucine at position 27. These changes reduce enzymatic cleavage and extend the peptide's persistence in circulation. The compound is discussed in two forms, one carrying a drug affinity complex and one without it.
The drug affinity complex is a maleimidopropionic acid group attached to a lysine side chain. It reacts with the free thiol of cysteine-34 on circulating albumin, forming a covalent bond. This conjugation keeps the peptide in the bloodstream and shields it from rapid renal filtration and proteolysis. Reported circulation half-lives for the albumin-bound form fall in the range of roughly six to nine days in early human studies.
Binding to GHRH receptors on pituitary somatotroph cells triggers cyclic AMP signaling and stimulates growth hormone synthesis and release. Because the peptide acts upstream of the pituitary, effects are mediated through endogenous growth hormone rather than direct receptor activation in peripheral tissues. Increases in insulin-like growth factor 1 are generally described as a downstream consequence. Most published human exposure data come from small early-stage studies, and the clinical significance of the pharmacokinetic profile remains incompletely characterized.
The distinguishing feature of the DAC form is a maleimide-containing group that reacts with the free thiol of cysteine-34 on human serum albumin. This reaction forms a covalent bond without enzymatic assistance, and it takes place after the peptide enters the bloodstream. Because albumin is abundant and long-lived, the attached peptide is carried through circulation far longer than an unmodified fragment would survive. The chemistry is a deliberate pharmacokinetic strategy rather than a change to receptor activity.
Enzymatic protection is a separate mechanism from plasma protein binding. The four substitutions in the backbone reduce recognition by dipeptidyl peptidase IV, which normally cleaves the natural hormone within minutes. Without the reactive group, this resistance still yields only a short window of activity, generally reported in the range of tens of minutes. With it, reported half-lives in early human work extended to several days. The size of that gap is the main practical distinction between the two materials.
Both forms act at the pituitary receptor for growth hormone-releasing hormone and increase growth hormone output, which in turn raises insulin-like growth factor 1. A long-acting analog produces sustained rather than pulsatile stimulation, and the physiological consequences of that pattern are not fully settled. Published human data on the extended form remain limited, and much of what circulates in discussion traces to early company reports rather than independent replication. How sustained exposure affects normal feedback remains an open question.
| Property | Value | Notes |
|---|---|---|
| Physical form | Lyophilized white powder | Supplied as a freeze-dried solid for research use |
| Molecular weight | Approximately 3,647 Da (DAC form) | Lower for the variant lacking the albumin-binding moiety |
| Solubility | Soluble in water and aqueous buffer | Typically dissolved in sterile or bacteriostatic water |
| Typical storage temperature | −20 °C or below | Dry powder, desiccated and protected from light |
| Common analytical method | Reversed-phase HPLC with mass spectrometry | Used for purity estimation and identity confirmation |
Binding of the peptide to the growth hormone-releasing hormone receptor on pituitary somatotrophs triggers a G protein coupled cascade that raises cyclic AMP and opens calcium channels. The result is greater secretion of growth hormone into the bloodstream. Because the peptide acts at the same receptor as the natural hypothalamic hormone, its effect is amplified pulse size rather than an entirely separate release pathway. Receptor binding alone does not determine the response, since somatostatin tone and other inputs modulate the final output.
The albumin-binding version stays in circulation for days, because covalent attachment to serum albumin shields the peptide from rapid filtration and degradation. Reported half-lives for this form fall in the range of several days. The version without the linker is cleared in minutes, with estimates often near thirty minutes in animal work. These figures come from small studies and vary with assay method, species, and route, so they are best read as approximate rather than fixed constants.
Lyophilised powder is the usual supplied form. The material is hygroscopic, so vials are typically equilibrated to room temperature before opening in order to prevent condensation on the contents. Long-term storage is generally described at minus twenty degrees Celsius or colder, protected from light and moisture. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of soluble material. A reconstituted solution is considerably less stable than the dry powder and is normally kept refrigerated for short periods only.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography combined with mass spectrometry. The chromatographic separation resolves the target peptide from truncation products and from species carrying oxidised residues, while mass measurement confirms the expected molecular mass. Because the two common variants differ by roughly 280 daltons, a mass determination distinguishes them unambiguously. Purity is often quoted as a percentage of total peak area, although that figure depends on the detection wavelength and the integration method applied.
Candidates were asked to give yes or no responses to whether or not January 6 was an "inside job" and whether or not the 2020 election was "stolen". Those that did not say yes to both answers were not hired.
== Further reading == Althouse BM, Hébert-Dufresne L (October 2014). "Epidemic cycles driven by host behaviour". Journal of the Royal Society, Interface. 11 (99) 20140575. doi:10.1098/rsif.2014.0575. PMC 4235258. PMID 25100316.
Because of the large energy distribution, ions with similar mass/charge ratio can have very different kinetic energies and will thus experience different deflection for the same magnetic field. In practical terms one would see that ions with the same mass/charge ratio focus at different points in space. However, in a mass-spectrometer one wants ions with the same mass/charge ratio to focus at the same point, e.g. where the detector is located. In order to overcome these limitations, commercial MC-ICP-MS are double-focusing instruments. In a double-focusing mass-spectrometer ions are focused due to kinetic energy by the ESA (electro-static-analyzer) and kinetic energy + mass/charge (momentum) in the magnetic field. Magnet and ESA are carefully chosen to match the energy focusing properties of one another and are arranged so that the direction of energy focusing is in opposite directions. To simplify, two components have an energy focus term, when arranged properly, the energy term cancels out and ions with the same mass/charge ratio focus at the same point in space. Double-focusing does not reduce the kinetic energy distribution and different kinetic energies are not filtered or homogenized. Double-focusing works for single as well as multi-collector instruments. In single collector instruments ESA and magnet can be arranged in either forward geometry (first ESA then magnet) or reversed geometry (magnet first then ESA), as only point-to-point focusing is required.
Sources: en.wikipedia.org
=== Senses === As with other sharks, white sharks use five senses when hunting: eyesight, hearing, smell (olfaction), electroreception (via pits called Ampullae of Lorenzini), and water flow detection (via a lateral line). Analysis of the brain and cranial nerves suggests that sight and smell are the most developed. The eyes of the white shark can appear solid black but have blue irises, and the pupil is more horizontal than in other sharks. The eyes have more cones than rods, indicating daytime vision. They lack nictitating membranes (a transparent third eyelid) but possess well-developed muscles that allow them to roll around to keep track of prey and roll back to avoid attacks. The white shark has a relatively large olfactory bulb, an adaptation for detecting scents across the open ocean. A vomeronasal organ, located in the roof of the mouth, also appears to play a role in smell.
The half-lives of nuclei in the island of stability itself are unknown since none of the nuclides that would be "on the island" have been observed. Many physicists believe that the half-lives of these nuclei are relatively short, on the order of minutes or days. Some theoretical calculations indicate that their half-lives may be long, on the order of 100 years, or possibly as long as 109 years. The shell closure at N = 184 is predicted to result in longer partial half-lives for alpha decay and spontaneous fission. It is believed that the shell closure will result in higher fission barriers for nuclei around 298Fl, strongly hindering fission and perhaps resulting in fission half-lives 30 orders of magnitude greater than those of nuclei unaffected by the shell closure. For example, the neutron-deficient isotope 284Fl (with N = 170) undergoes fission with a half-life of 2.5 milliseconds, and is thought to be one of the most neutron-deficient nuclides with increased stability in the vicinity of the N = 184 shell closure. Beyond this point, some undiscovered isotopes are predicted to undergo fission with still shorter half-lives, limiting the existence and possible observation of superheavy nuclei far from the island of stability (namely for N < 170 as well as for Z > 120 and N > 184). These nuclei may undergo alpha decay or spontaneous fission in microseconds or less, with some fission half-lives estimated on the order of 10−20 seconds in the absence of fission barriers.
== Selected articles == McCartney, Fiona; Jannin, Vincent; Chevrier, Stéphanie; Boulghobra, Hakime; Hristov, Delyan R.; Ritter, Nicolas; Miolane, Cédric; Chavant, Yann; Demarne, Frédéric; Brayden, David J. (2019). "Labrasol® is an efficacious intestinal permeation enhancer across rat intestine: Ex vivo and in vivo rat studies". Journal of Controlled Release. 310: 115–126. doi:10.1016/j.jconrel.2019.08.008. PMID 31401199. Hristov, Delyan; McCartney, Fiona; Beirne, Jason; Mahon, Eugene; Reid, Stephanie; Bhattacharjee, Sourav; Penarier, Geraldine; Werner, Ulrich; Bazile, Didier; Brayden, David J. (2020). "Silica-coated nanoparticles with a core of zinc, l-Arginine, and a peptide designed for oral delivery". ACS Applied Materials & Interfaces. 12 (1): 1257–1269. Bibcode:2020AAMI...12.1257H. doi:10.1021/acsami.9b16104. PMID 31802658. Twarog, Caroline; Liu, Kai; O'Brien, Peter J.; Dawson, Kenneth A.; Fattal, Elias; Illel, Brigitte; Brayden, David J. (2020). "A head-to-head Caco-2 assay comparison of the mechanisms of action of the intestinal permeation enhancers: SNAC and sodium caprate (C10)". European Journal of Pharmaceutics and Biopharmaceutics. 152: 95–107. doi:10.1016/j.ejpb.2020.04.023. PMID 32387703. Khandelia, Rumi; Hodgkinson, Tom; Crean, Daniel; Brougham, Dermot F.; Scholz, Dimitri; Ibrahim, Hossam; Quinn, Susan J.; Rodriguez, Brian J.; Kennedy, Oran D.; O’Byrne, John M.; Brayden, David J. (2024). "Reproducible synthesis of biocompatible albumin nanoparticles designed for intra-articular administration of celecoxib to treat osteoarthritis".
Sources: en.wikipedia.org
The two share the same 29-amino-acid backbone. CJC-1295 carries an additional albumin-binding moiety that markedly extends its residence time in circulation, while the form without that moiety clears faster. Literature sometimes applies the name loosely to either variant.
It has not been approved by major regulatory agencies for any therapeutic indication. Material sold under this name is typically distributed for laboratory research only. Clinical use is not supported by large controlled trials.
Early human studies of the albumin-binding form reported circulation half-lives on the order of several days. The value depends on assay method and study design. Estimates for the form without the binding moiety are considerably shorter.
A maleimide moiety reacts with the thiol of cysteine-34, forming a covalent bond. The reaction occurs in circulation without enzymatic catalysis.