If you have been reading about IGF-1 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.
Last reviewed on 2026-06-13. Where a claim depends on a specific study, the study is described rather than over-claimed.
CJC-1295 is a synthetic peptide designed to mimic growth hormone-releasing hormone (GHRH), the endogenous signal that prompts the pituitary gland to release growth hormone. The compound is a modified fragment of the natural hormone, spanning the first twenty-nine amino acids of GHRH with several substitutions that slow enzymatic breakdown. Two variants circulate in research settings: one carrying a drug affinity complex (DAC) and one without it. The DAC-free form is frequently labelled Mod GRF(1-29) in catalogs and discussion forums.
The peptide binds GHRH receptors on somatotroph cells within the anterior pituitary, triggering a signalling cascade that increases growth hormone secretion. Its improved resistance to dipeptidyl peptidase IV degradation distinguishes it from the parent hormone. In the DAC-bearing version, a maleimide group reacts with a cysteine residue on serum albumin, forming a covalent bond that keeps the peptide in circulation far longer. That albumin attachment is the central design feature separating the two research variants.
Pharmacokinetic behaviour differs sharply between the two forms. The DAC-bearing peptide shows an extended circulation time measured in days, whereas the version without the complex is cleared within roughly half an hour. This gap shapes how researchers design dosing schedules in animal models. Whether the prolonged presence of the DAC form produces effects meaningfully different from the short-acting variant remains an open question, since comparative human data are scarce.
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.
Studies in this area generally track growth hormone pulses, insulin-like growth factor 1 concentrations, and occasionally body composition endpoints. Most published human data come from early, small trials, and questions about long-term effects remain open. Whether repeated exposure alters pituitary responsiveness over time is not settled. Analytical work relies on immunoassays for the hormones and on mass spectrometry for the peptide itself, because the two measurements answer different questions.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular weight (with DAC) | ~3647 Da | Calculated from the full amino acid sequence |
| Molecular weight (without DAC) | ~3368 Da | Mod GRF(1-29) variant |
| Appearance | White lyophilized powder | Typical form supplied for research |
| Solubility | Soluble in water | Dissolves in aqueous buffers |
| Receptor target | GHRH receptor | Expressed on pituitary somatotroph cells |
Characterization of this peptide relies on a small set of routine techniques. Reversed-phase high-performance liquid chromatography separates the target from truncated or oxidized by-products and yields a purity estimate when paired with ultraviolet detection near 214 nanometers. Mass spectrometry, either electrospray coupled to liquid chromatography or matrix-assisted laser desorption, confirms that the observed mass matches the value calculated for the expected sequence. Amino acid analysis, and enzymatic digestion followed by fragment mapping, are used when the sequence itself rather than the mass requires verification.
Stability depends heavily on physical state. A lyophilized powder kept dry, desiccated, and shielded from light typically holds its integrity for months to years at minus twenty degrees Celsius, and longer at minus eighty. Once dissolved, the peptide becomes far more vulnerable, since peptide bond hydrolysis, oxidation of susceptible residues, and aggregation all proceed faster in solution. Buffers near neutral pH are generally gentler than strongly acidic or alkaline conditions. Repeated freeze-thaw cycles and exposure to air-liquid interfaces during vigorous mixing cause losses that are easy to overlook.
Verification matters because research peptides vary widely in quality. A certificate of analysis is only as reliable as the method behind it, and a single chromatographic trace reveals little about counter-ions, residual solvents, or water content. Independent laboratories commonly pair mass confirmation with chromatographic purity and, where relevant, quantify water along with acetate or trifluoroacetate content. Reported purity figures are not standardized across suppliers, so a stated value such as ninety-eight percent is not directly comparable unless the analytical method, column, and detection wavelength accompany it.
Clearance profiles diverge sharply between the two versions. The albumin-binding molecule stays in plasma for several days, whereas the unmodified analog is largely gone within about half an hour in reported work. Cleavage by dipeptidyl peptidase IV is a major contributor to the short life of the unmodified sequence. These gaps mean the two versions cannot be substituted for each other in study design or in reading results side by side.
Reports on this compound commonly follow serum growth hormone and insulin-like growth factor 1 across defined time windows. Protocols differ in sampling frequency, assay platform, and participant characteristics, which makes direct comparison between publications difficult. Some work focuses on pulsatile release patterns instead of average concentrations. Whether repeated exposure alters endogenous hormone rhythms over long periods remains an open question, and the formal literature is thinner than the volume of informal commentary implies.
Once in circulation, the peptide binds the growth hormone-releasing hormone receptor displayed on pituitary somatotroph cells. Receptor activation couples to Gs proteins, elevates intracellular cyclic AMP, and drives protein kinase A signaling inside the cell. That cascade increases discharge of growth hormone into the bloodstream. The analog therefore operates through a receptor pathway that already exists for the body's own releasing hormone, rather than through an engineered artificial target.
In March 1924, having briefly considered the possibility of removing the offending article from the treaty, the government suspended any further negotiations; within six months they withdrew their support in favour of their central Arabian ally Ibn Saud, who proceeded to conquer Hussein's kingdom.
dopaquinone → leucodopachrome → dopachrome → 5,6-dihydroxyindole-2-carboxylic acid → quinone → eumelanin dopaquinone → leucodopachrome → dopachrome → 5,6-dihydroxyindole → quinone → eumelanin Detailed metabolic pathways can be found in the KEGG database (see External links).
By the Palaiologan period, the dominance of strict compositional rules lessened and John Koukouzeles led a new school favouring a more ornamental "kalophonic" style which deeply informed post-empire Neo-Byzantine music. Secular music, often state-sponsored, was ubiquitous in daily life and featured in a variety of ceremonies, festivals, and theatre. Secular vocal music was rarely notated, and extant manuscripts date much later, suggesting the tradition was passed through oral tradition and likely improvised. Prohibited for liturgical use, a wide variety of Byzantine instruments flourished in secular contexts, although no notated instrumental music survives. It is uncertain to what extent instrumentalists improvised or if they doubled vocalists monophonically or heterophonically. Among the best known instruments are the hydraulic organ, used for circus and imperial court events; the ancient Greek-descended aulos, a wind instrument; the tambouras, a plucked string instrument; and mostly popularly, the Byzantine lyra. Prominent genres included acclamation chants of laudation or salutation; the celebratory Acritic songs; symposia instrumental banquets, based on ancient symposiums; and dance music.
Copper-free click chemistry is being explored for use in synthesizing PET imaging agents which must be made quickly with high purity and yield in order to minimize isotopic decay before the compounds can be administered. Both the high rate constants and the bioorthogonality of SPAAC are amenable to PET chemistry.
Sources: en.wikipedia.org
== Functions and binding properties == Such a broad pattern in gene expression over such a wide range of sensory and non-sensory fluids or tissues is in strong agreement with a very general basic function for this gene family, i.e. in relation with lipid transport and metabolism. A role of CSPs in general immunity, insecticide resistance and xenobiotic degradation has been recently brought up by Xuan et al. (2015), who showed a drastic and remarkable up-regulation of CSP genes in many various tissues over exposure to abamectin insecticide molecule [32]. Increased load of CSPs (pherokines) in fly hemolymph is observed after microbial or viral infection [33]. The particular role of CSP proteins in lipid transport in relation with insecticide resistance has been brought up by Liu et al. (2016) in whiteflies [34]. Liu et al. showed insecticide-mediated up regulation and interaction of the protein with C18-lipid (linoleic acid), suggesting a metabolic role of CSP in insect defense rather than olfaction or chemical communication [34]. The first member of this soluble protein family has been reported by Nomura et al. (1982) as up-regulated factor (p10) in the regenerating legs of the American cockroach Periplaneta americana [35]. The same protein was identified in the antennae and legs from P. americana at the adult sexually mature stage with some apparent differences between males and females, rather suggesting a “chemodevol” function for this protein, contributing both to tissue development and recognition of sex-specific signals such as sex pheromones [2].
are the concentrations of the solute's ionic constituents in a saturated solution. The solubility product is derived from and functions like the equilibrium constant of dissociation, though unlike an equilibrium constant it is not dimensionless. If the product of ionic concentrations in a solution exceeds the solubility product, then precipitation occurs.
EosFP is a photoactivatable green to red fluorescent protein. Its green fluorescence (516 nm) switches to red (581 nm) upon UV irradiation of ~390 nm (violet/blue light) due to a photo-induced modification resulting from a break in the peptide backbone near the chromophore. Eos was first discovered as a tetrameric protein in the stony coral Lobophyllia hemprichii. Like other fluorescent proteins, Eos allows for applications such as the tracking of fusion proteins, multicolour labelling and tracking of cell movement. Several variants of Eos have been engineered for use in specific study systems including mEos2, mEos4 and CaMPARI.
Sources: en.wikipedia.org
The synthetic peptide keeps the receptor-binding region of GHRH but carries substitutions that resist enzymatic cleavage. In the DAC version, an added group also anchors the molecule to albumin, extending its presence in the bloodstream.
The maleimide group forms a covalent link with albumin, an abundant blood protein. This attachment slows clearance, so a single administration persists much longer than the unmodified peptide. The feature is the main reason the two variants are handled differently in study design.
It is not an approved therapeutic product in major regulatory jurisdictions. It appears in research chemical catalogs and scientific literature rather than pharmacy shelves. Clinical development was limited and did not reach approval.
Reported values cluster in the range of several days, reflecting slow release from the albumin complex. Estimates differ across species and assay platforms. The figure describes circulation time in study settings rather than a fixed property.