The short version of somatotroph fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
Four amino acid substitutions separate the modified backbone from the parent GRF(1-29) sequence. These changes reduce recognition by dipeptidyl peptidase IV and related proteases, extending the interval before degradation. Development work in this area sought longer-acting GHRH analogs for endocrine investigation. Published descriptions treat the substitution set as a defining property of the core sequence, while the albumin-binding linker is described separately as an optional addition to that same backbone.
CJC-1295 is a synthetic peptide analog of growth hormone-releasing hormone, constructed on the 29-amino-acid fragment designated GRF(1-29). The name began as an internal development code during the 1990s and later spread through research supply catalogs and discussion forums. The molecule does not occur in nature; its sequence is engineered rather than isolated from tissue. Two related compounds are sold under this single label, and they differ by one appended chemical group that strongly influences how long the peptide remains in circulation.
The dividing feature between the two forms is a maleimide-based drug affinity complex, abbreviated DAC. In the DAC-bearing version, a linker attaches the peptide to serum albumin after administration, and that association slows removal from plasma. The version lacking DAC appears in catalogs as MOD GRF(1-29) or tetrasubstituted GRF(1-29). Because informal writing treats both as one item, comparisons drawn from such sources routinely blend measurements taken from two molecules with substantially different behavior.
Downstream of growth hormone, the liver and other tissues increase production of insulin-like growth factor 1, a mediator of many growth-promoting effects. Studies have documented elevated levels of both hormones after dosing, and the rise from the long-acting form persists longer than that produced by shorter-acting analogues. What remains unclear is whether sustained elevation of these markers translates into meaningful clinical benefit, and whether prolonged exposure carries risks that short trials could not detect.
CJC-1295 acts at the growth hormone-releasing hormone receptor, a G-protein-coupled receptor found on somatotroph cells in the anterior pituitary. Binding triggers a rise in cyclic AMP and calcium entry, which promotes release of stored growth hormone. Because the peptide mimics the body's own releasing hormone, it amplifies existing secretory pulses rather than driving continuous output. The size of the response therefore depends partly on the subject's own hormonal rhythm and feedback state.
The attached maleimide group explains the unusual duration of the DAC version. After injection it reacts with the thiol of cysteine-34 on serum albumin, forming a stable covalent bond. The resulting conjugate is too large for rapid kidney filtration and is shielded from many peptidases. Reported half-lives for this form reach several days, whereas the version without the group is cleared in roughly half an hour. That gap is the main pharmacological difference between the two.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | Analog of growth hormone-releasing hormone |
| Chain length | 29 amino acids | Based on the GRF(1-29) fragment |
| Appearance | White to off-white lyophilized powder | Common research supply form |
| Solubility | Soluble in water and aqueous buffers | Powder requires reconstitution before use |
| Typical storage | −20 °C or below | Kept away from light and moisture |
The core sequence keeps the receptor-binding region of GHRH while replacing four positions that are vulnerable to dipeptidyl peptidase-4 and other proteases. Substitutions at positions 2, 8, 15, and 27 raise metabolic stability relative to the natural hormone. The N-terminal residues remain essential for activity, so changes there generally lower potency. Molecular weight sits near 3368 daltons for the tetrasubstituted analog without the linker, while the albumin-binding form is heavier because of the added maleimide group.
CJC-1295 is a synthetic peptide modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. Its sequence corresponds to the first twenty-nine residues of human GHRH, with four substitutions that slow enzymatic breakdown. Early descriptions placed the compound in research on growth hormone deficiency and related conditions, and later literature groups it with the long-acting GHRH analogs. The name appears in both laboratory and popular fitness writing, where it sometimes labels chemically different peptides.
Two related peptides circulate under the CJC-1295 label, and they differ mainly in how long they persist in circulation. The version carrying a drug affinity complex includes a maleimidopropionic acid linker that forms a covalent bond with serum albumin. The other version, usually written as modified GRF(1-29) or tetrasubstituted GRF(1-29), lacks that linker and is cleared quickly. Mixing the two produces inconsistent readings of published half-life values, because the linker rather than the receptor-facing sequence drives most of the difference.
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.
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.
Research material is normally supplied as a freeze-dried powder in sealed vials. In that state the peptide is comparatively robust, but prolonged exposure to warmth, moisture, or light accelerates degradation. Storage at minus twenty degrees Celsius or lower, with desiccant and protection from light, is the commonly described practice. Vials should be allowed to reach room temperature before opening to limit condensation on the powder. Moisture uptake during handling is a recognized source of variability in later measurements.
Reconstitution is typically performed with sterile water or bacteriostatic water, added slowly against the vial wall. The resulting solution should be clear and colorless; cloudiness or visible particles suggest a problem with the material or the diluent. Once in solution, the peptide is less stable than the dry powder. Refrigerated storage at two to eight degrees Celsius is common for short-term holding, while freezing aliquots is described for longer periods.
Two related forms appear under the CJC-1295 name. The simpler analogue, commonly written as modified GRF(1-29), carries the four substitutions but no additional conjugation. The second form attaches a maleimidopropionic acid linker to a lysine residue, a modification frequently called the drug affinity complex. That linker reacts with the free thiol on serum albumin to form a covalent bond. Because albumin has a long residence time in blood, the conjugated peptide stays in circulation far longer than the unconjugated analogue.
Receptor level activity follows the canonical GHRH pathway. The peptide binds the GHRH receptor, a class B G protein coupled receptor on somatotroph cells of the anterior pituitary. Binding raises intracellular cyclic AMP, which promotes calcium entry and the release of growth hormone into the bloodstream. Because the molecule acts at the same receptor as the endogenous hormone, its effect is superimposed on the natural pulsatile rhythm rather than replacing it. Whether sustained receptor occupation leads to desensitization is not fully settled.
=== Pervasive expression === With the development of technologies such as RNA-seq and Ribo-seq, eukaryotic genomes are now known to be pervasively transcribed and translated. Many ORFs that are either unannotated, or annotated as long non-coding RNAs (lncRNAs), are translated at some level, either in a condition or tissue-specific manner. Though infrequent, these translation events expose non-genic sequence to selection. This pervasive expression forms the basis for several models describing de novo gene birth. It has been speculated that the epigenetic landscape of de novo genes in the early stages of formation may be particularly variable between and among populations, resulting in variable gene expression thereby allowing young genes to explore the "expression landscape." The QQS gene in A. thaliana is one example of this phenomenon; its expression is negatively regulated by DNA methylation that, while heritable for several generations, varies widely in its levels both among natural accessions and within wild populations. Epigenetics are also largely responsible for the permissive transcriptional environment in the testes, particularly through the incorporation into nucleosomes of non-canonical histone variants that are replaced by histone-like protamines during spermatogenesis.
=== Gene therapy prior to conception === Mitochondrial replacement therapy (MRT), where the nuclear DNA is transferred to another healthy egg cell leaving the defective mitochondrial DNA behind, is an IVF treatment procedure. Using a similar pronuclear transfer technique, researchers at Newcastle University led by Douglass Turnbull successfully transplanted healthy DNA in human eggs from women with mitochondrial disease into the eggs of women donors who were unaffected. In such cases, ethical questions have been raised regarding biological motherhood, since the child receives genes and gene regulatory molecules from two different women. Using genetic engineering in attempts to produce babies free of mitochondrial disease is controversial in some circles and raises important ethical issues. A male baby was born in Mexico in 2016 from a mother with Leigh syndrome using MRT. In September 2012 a public consultation was launched in the UK to explore the ethical issues involved. Human genetic engineering was used on a small scale to allow infertile women with genetic defects in their mitochondria to have children. In June 2013, the United Kingdom government agreed to develop legislation that would legalize the 'three-person IVF' procedure as a treatment to fix or eliminate mitochondrial diseases that are passed on from mother to child. The procedure could be offered from 29 October 2015 once regulations had been established.
With insect stings, a large local reaction may occur as an area of skin redness greater than 10 cm in size that can last one to two days. This reaction may also occur after immunotherapy. The skin forms an effective barrier to the entry of most allergens, but this barrier cannot withstand everything. For example, an insect sting can breach the barrier and inject allergen into the affected spot. When an allergen enters the epidermis or dermis, it triggers a localized allergic reaction which activates the mast cells in the skin resulting in an immediate increase in permeability of blood vessels, leading to fluid leakage and swelling in the affected area. Mast-cell activation also stimulates a skin lesion called the wheal-and-flare reaction. Then the release of chemicals from local nerve endings by a nerve axon reflex causes the widening of surrounding cutaneous blood vessels, which causes redness of the surrounding skin. As part of the allergic response, the body has developed a secondary response that, in some individuals, causes a more widespread and sustained skin swelling. This usually occurs about 8 hours after the allergen originally comes in contact with the skin. When an allergen is ingested, a dispersed form of wheal-and-flare reaction, known as urticaria or hives, will appear when the allergen enters the bloodstream and eventually reaches the skin. This same skin reactivity allows allergists to test for existing allergies by injecting a small amount of an allergen into the skin, which causes a reaction at the injection site.
123I is produced by proton irradiation of 124Xe. The caesium isotope produced is unstable and decays to 123I. The isotope is usually supplied as the iodide and hypoiodate in dilute sodium hydroxide solution, at high isotopic purity. 123I has also been produced at Oak Ridge National Laboratories by proton bombardment of 123Te. 123I decays by electron capture with a half-life of 13.22 hours. The emitted 159 keV gamma ray is used in single-photon emission computed tomography (SPECT). A 127 keV gamma ray is also emitted. 125I is frequently used in radioimmunoassays because of its relatively long half-life (59 days) and ability to be detected with high sensitivity by gamma counters. 129I is present in the environment as a result of the testing of nuclear weapons in the atmosphere. It was also produced in the Chernobyl and Fukushima disasters. 129I decays with a half-life of 15.7 million years, with low-energy beta and gamma emissions. It is not used as a tracer, though its presence in living organisms, including human beings, can be characterized by measurement of the gamma rays.
Isotope masses from: Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001 Isotopic compositions and standard atomic masses from: de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683. Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051. "News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005. Half-life, spin, and isomer data selected from the following sources. Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001 National Nuclear Data Center. "NuDat 3.0 database". Brookhaven National Laboratory. Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.
Sources: en.wikipedia.org
==== Pilosan research ==== Casali et al. (2026) identify a poorly developed dental alveolus in a specimen of Nothrotherium maquinense from the Pleistocene strata from Brazil, occupying the position of caniniform alveolus in Neogene nothrotheriids, and interpreted as a possible case of partial re-expression of a lost ancestral dental condition in the studied individual. Revision of nematheriine scelidotheriid sloths from the Miocene Santa Cruz Formation (Argentina) is published by Boscaini et al. (2026), who assign all studied fossils to the genus Nematherium, with the majority of them assigned to the species N. angulatum New fossil material of Ocnotherium giganteum, including a nearly complete skull and two partial skeletons, is described from the Pleistocene strata from Brazil by Pujos et al. (2026), who recover O. giganteum as a mylodontine mylodontid. Evidence from the study of a mylodontid coprolite from the Pleistocene strata from the Cueva Cacao 1.A site (Argentina) indicative of a grazing-browsing dietary niche of the producer is presented by Velázquez et al. (2026). Zicos et al. (2026) compare the utility of three ancient DNA extraction methods for recovery of DNA from coprolites of Mylodon darwinii and soil samples from Cueva del Milodón (Chile), and report recovery of both sloth mitochondrial genomes and signatures of local flora. Harper et al.
Since the beginning of the 21st century, fast food has been criticized for its animal welfare record, its links to obesity and its environmental impact. Eric Schlosser's book Fast Food Nation (2002) and Morgan Spurlock's film Super Size Me (2004) reflected these concerns. Since 2003, People for the Ethical Treatment of Animals (PETA) has protested KFC's choice of poultry suppliers worldwide. The exception is KFC Canada, which signed an agreement pledging to only use "animal-friendly" suppliers. President of KFC's US division Gregg Dedrick said PETA mischaracterized KFC as a poultry producer rather than a purchaser of chickens. In 2008, Yum! stated: "[As] a major purchaser of food products, [Yum!] has the opportunity and responsibility to influence the way animals supplied to us are treated. We take that responsibility very seriously, and we are monitoring our suppliers on an ongoing basis." In 2006, Greenpeace accused KFC Europe of sourcing the soya bean for its chicken feed from Cargill, which had been accused of clearing large swathes of the Amazon rainforest in order to grow the crop. In 2010, according to The Guardian, "in the US where fried chicken remains closely associated with age-old racist stereotypes about black people in the once segregated south", KFC Australia aired the 30-second promotion on television named "KFC's cricket survival guide" which shows a white cricket fan surrounded by black fans from the opposing team.
These normal pathways plan a key role in "mediation of Fyn transmitted cellular events impacting shape and motility." A compromised version of this pathway would enable cancer cells to change shape and motility, increasing the possibility for advanced invasion and metastasis. Additional pathways under investigation regarding Fyn's role in cancer progression include: the Rac and Rho family of GTPases, Ras, Erk, and MAPK. Because of this, Fyn has been a common target for anti-cancer therapeutic research. The inhibition of Fyn (like other SFKs) results in decreased cell growth. Furthermore, "expression of kinase-dead-Fyn (KD-Fyn), a specific competitor of endogenous Fyn," was found to reduce the size of primary tumors in mice. Specifically targeting the unique identifying properties of Fyn as well as inhibiting FAK and PXN has the potential to create a very effective molecularly targeted combination cancer therapy. Fyn inhibitors are also being explored as potential therapies for Alzheimer's Disease.
The formylglycine tag or aldehyde tag is a convenient 6- or 13-amino acids long tag fused to a protein of interest. The 6-mer tag represents the small core consensus sequence and the 13-mer tag the longer full motif. The experiments on the genetically encoded aldehyde tag by clearly showed the high conversion efficiency with only the core consensus sequence present. Four proteins were produced recombinantly in E.coli with an 86% efficiency of for the full-length motif and >90% efficiency for the 6-mer determined by mass spectrometry. The size of the sequence is analogous to the commonly used 6x His-Tag and has the advantage that it can also be genetically encoded. The sequence is recognized in the ER solely depending on primary sequence and subsequently targeted by FGE. Notably, in the setup of recombinant expression proteins in E. coli a coexpression of exogenous FGE aids full conversion, although E. coli has endogenous FGE-activity. The introduction of an aldehyde tag has a workflow that consists of three segments: A the expression of the fusion protein, that carries the peptide tag derived from the sulfatase motif, B the enzymatic conversion of Cys to f(Gly) and C the bioorthogonal probing with hydrazides or alkoxy amines (Fig. 1).
Profilin allergy is significantly associated with respiratory allergy to grass pollen ( hay fever). After a person first becomes allergic to profilin through inhalation of grass or tree pollen, allergy to profilin-containing food and development of pollen-food syndrome occurs How often pollen-allergic people across Europe become profilin allergic varies widely; As of 1997, from about 5% of Swedish birch pollen–allergic people to 51% in Spanish people allergic to Mercurialis annua were profilin allergic. Profilin is the major allergen of certain food plants, for example, melon, orange, and soybean and thus allergy to melon, citrus fruits, tomato, and banana is a clinical marker of profilin hypersensitivity. As of 2018 there was no "solid therapeutic approach" to treat profilin allergy. As of 2018, the list of members of the profilin family identified as allergens contained:
Sources: en.wikipedia.org
The world annual production of the various species of Chlorella was 2000 tonnes (dry weight) in 2009, with the main producers being Germany, Japan and Taiwan. C. vulgaris is a candidate for commercial production due to its high resistance against adverse conditions and invading organisms. In addition, the production of the various organic macromolecules of interest (proteins, lipids, starch) differ depending on the technique used to create biomass and can be therefore targeted. Under more hostile conditions, the biomass decreases, but lipids and starch contents increase. Under nutrient and light-replete conditions, protein content increases along with the biomass. Different growth techniques have been developed. Different modes of growth (autotrophic, heterotrophic, and mixotrophic) has been investigated for Chlorella vulgaris; autotrophic growth is favoured as it does not require provision of costly organic carbon and relies on inorganic carbon sources (CO2, carbonates) and light for photosynthesis. Chlorella sp. cultivated in digested and membrane-pretreated swine manure is capable of improving the growth medium performance of microalgae cultivations in terms of final biomass productivity, showing that algal growth depends on the turbidity of liquid digestate streams rather than on their nutrient availability.
Heavy chain contains similar gene segments such as VH, JH, and CH, but also has another gene segment called D (diversity). Unlike the light chain multigene family, VDJ gene segments code for the variable region of the heavy chain. The rearrangement and reorganization of gene segments in this multigene family is more complex . The rearranging and joining of segments produced different end products because these are carried out by different RNA processes. The same reason is why the IgM and IgG are generates at the time. The variable region rearrangements happen in an orderly sequence in the bone marrow. Usually, the assortment of these gene segments occurs at B cell maturation.
58. Dermatol Online J. 2018 May 15;24(5):13030/qt2gz9f9jk. A glimpse into the underground market of melanotan. Callaghan Iii DJ(1). Author information: (1)Department of Dermatology, Boston Medical Center, Boston, Massachusetts. danieljcallaghan3@gmail.com. Melanotan-I and melanotan-II are alpha-melanocyte stimulating hormone (a-MSH) analogues that can be purchased illicitly online with relative ease and are injected subcutaneously to stimulate a tan. Little is known about the use of these unregulated substances. An observational survey was posted to an online forum in which participants share their experiences using melanotan-I or melanotan-II. Users were asked to complete this voluntary, anonymous survey, which had questions focusing on motivation and hesitation for and against using melanotan, difficulty in acquiring it, and plans for continuing to use melanotan in the future.
Later it was shown in ab initio calculations with the high level of accuracy that the Rf atom has the ground state with the 6d2 7s2 valence configuration and the low-lying excited 6d1 7s2 7p1 state with the excitation energy of only 0.3–0.5 eV. In an analogous manner to zirconium and hafnium, rutherfordium is projected to form a very stable, refractory oxide, RfO2. It reacts with halogens to form tetrahalides, RfX4, which hydrolyze on contact with water to form oxyhalides RfOX2. The tetrahalides are volatile solids existing as monomeric tetrahedral molecules in the vapor phase. In the aqueous phase, the Rf4+ ion hydrolyzes less than titanium(IV) and to a similar extent as zirconium and hafnium, resulting in the RfO2+ ion. Treatment of the halides with halide ions promotes the formation of complex ions. The use of chloride and bromide ions produces the hexahalide complexes RfCl2−6 and RfBr2−6. For the fluoride complexes, zirconium and hafnium tend to form hepta- and octa- complexes. Thus, for the larger rutherfordium ion, the complexes RfF2−6, RfF3−7 and RfF4−8 are possible.
Sources: en.wikipedia.org
No. It is a laboratory-synthesized analog built on a fragment of the natural hormone. The natural peptide is shorter-lived and lacks the stabilizing substitutions found in the synthetic version.
DAC stands for drug affinity complex, a chemical group that binds the peptide to serum albumin. The binding slows clearance and lengthens the time the molecule stays in plasma compared with the unmodified analog.
Because two distinct molecules are discussed under one informal label. The albumin-binding version clears over several days, while the form without that group clears within roughly half an hour. Mixing results from both creates inconsistent figures.
It binds the growth hormone-releasing hormone receptor on pituitary somatotroph cells. Receptor activation raises cyclic AMP and promotes release of stored growth hormone granules. Because the peptide persists longer than natural releasing hormone, stimulation is prolonged rather than brief.