The short version of somatotroph fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-01-17. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| 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 |
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.
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.
Reported half-lives differ widely between the two variants and between species. Values for the albumin-binding form are usually expressed in days, while the unconjugated form is measured in minutes to a few hours. Sampling schedules, assay sensitivity, and route of administration all influence the numbers, which limits direct comparison across studies. Whether sustained receptor occupancy produces different downstream effects from pulsatile stimulation remains an open question in the published work. Claims about relative potency should therefore be read alongside the specific study design that produced them.
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.
=== Brewing fresh leaves === To prepare mint tea from fresh leaves, the leaves are harvested, washed, and placed in boiling water for a few minutes. While fresh and dried leaves have similar flavors, some studies suggest that tea brewed with fresh leaves produces a fresher, more aromatic experience.
== Side effects == Among antibiotic drugs, meropenem is relatively safe. The most common adverse effects are diarrhea (4.8%), nausea and vomiting (3.6%), injection-site inflammation (2.4%), headache (2.3%), rash (1.9%) and thrombophlebitis (0.9%). Many of these adverse effects were observed in severely ill individuals already taking many medications including vancomycin. Meropenem has a reduced potential for seizures in comparison with imipenem. Several cases of severe hypokalemia have been reported.
After the war, he returned to Minnesota where he worked on geochronology, the upper atmosphere, space science and noble gases. Nier designed the miniature mass spectrometers used by the Viking Landers to sample the atmosphere of Mars.
Jon Wiederhorn of Rolling Stone called the album "liberating and enlightening, the songs achieve a startling, staggering and palpable impact." The band released the home video The Nona Tapes On December 12, a mockumentary featuring interviews with the band members conducted by journalist Nona Weisbaum (played by Jerry Cantrell), and the music video for "Grind". The band opted not to tour in support of Alice in Chains, adding to the rumors of drug abuse. The song "Got Me Wrong" unexpectedly charted three years after its release on the Sap EP. The song was re-released as a single on the soundtrack for the film Clerks in 1994, reaching number seven on the Mainstream Rock Tracks chart. Alice in Chains resurfaced on April 10, 1996, to perform for MTV Unplugged, a program featuring all-acoustic set lists. The performance featured some of the band's highest-charting singles, including "Rooster", "Down in a Hole", "Heaven Beside You", "No Excuses" and "Would?", and introduced a new song, "Killer Is Me", with Cantrell on lead vocals. The show marked Alice in Chains' only appearance as a five-piece band, adding second guitarist Scott Olson. A live album of the performance was released in July 1996, which debuted at number three on the Billboard 200, and was accompanied by a home video release, both of which received platinum certification by the RIAA. The band also appeared on The Late Show with David Letterman on May 10, 1996, performing the songs "Again" and "We Die Young".
Sources: en.wikipedia.org
== Books == Seven and a Half Lessons About the Brain. Houghton Mifflin Harcourt, 2020. ISBN 0358157145. How Emotions are Made: The Secret Life of the Brain. Houghton Mifflin Harcourt, 2017. ISBN 0544133315. Handbook of Emotions, Fourth Edition. Guilford Fubn, 2018 The Psychological Construction of Emotion, Guilford Fubn, 2014
== External links == IFR/JIC TOF MS Tutorial Jordan TOF Products TOF Mass Spectrometer Tutorial University of Bristol TOF-MS Tutorial Kore Technology – Introduction to Time-of-Flight Mass Spectrometry
Epitiostanol, also known as 2α,3α-epithio-4,5α-dihydrotestosterone (2α,3α-epithio-DHT) or as 2α,3α-epithio-5α-androstan-17β-ol, is a synthetic androstane steroid and a derivative of DHT. Mepitiostane, a derivative of epitiostanol with a C17α methoxycyclopentane ether substitution, is an orally active prodrug of epitiostanol. Another derivative, methylepitiostanol (2α,3α-epithio-17α-methyl-5α-androstan-17β-ol), has a methyl group at the C17α position and is similarly an orally active variant of epitiostanol; it has surfaced as a novel designer steroid.
Sources: en.wikipedia.org
== Natural product syntheses and other reactions == The total synthesis of quadrigemine C involves a double Stille cross metathesis reaction. The complex organostannane is coupled onto two aryl iodide groups. After a double Heck cyclization, the product is achieved.
== Types of decay == The four most common modes of radioactive decay are: alpha decay, beta decay, inverse beta decay (considered as both positron emission and electron capture), and isomeric transition. Of these decay processes, only alpha decay (fission of a helium-4 nucleus) changes the atomic mass number (A) of the nucleus, and always decreases it by four. Because of this, almost any decay will result in a nucleus whose atomic mass number has the same residue mod 4. This divides the list of nuclides into four classes, each of which forms a main decay chain. Three of these are readily observed in nature, commonly called the thorium series, the radium or uranium series, and the actinium series, representing three of these four classes, and ending in three different, stable isotopes of lead. The mass number of every isotope in the chain can be represented as A = 4n, A = 4n + 2, or A = 4n + 3, respectively. The long-lived starting isotopes of these three isotopes, respectively thorium-232, uranium-238, and uranium-235, have existed since the formation of the Earth, ignoring the artificial isotopes and their decays created since the 1940s. Due to the relatively short half-life of its starting isotope neptunium-237 (2.144 million years), the fourth chain, the neptunium series with A = 4n + 1, is already extinct in nature, except for the final rate-limiting step, decay of bismuth-209. Traces of 237Np and its decay products do occur in nature, however, as a result of neutron reactions in uranium ore; neutron capture by natural thorium to give 233U is also possible.
== Intracrines in biology and cancer == Intracrines involvement in cancer is primarily through their regulation of growth factors, angiogenesis, and cellular signaling networks that contribute to tumor growth and therapy resistance.
=== Nick: The Truck Stops Here === First aired: 11 November 2010 Meet Nick, he is a bully who calls himself "The Truck". He's both a singer in a Death Metal band and an in-line skater who makes life miserable for his victims, Chris and Blair. Mayhem Miller brings in legendary MMA fighter, Jeremy Horn to stop the truck once and for all. Nick tapped out five times in the first round, and got knocked out in the second round with a kick to the body. Chris and Blair won $10,000 and an apology from Nick.
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.
The names are often used interchangeably in casual writing, but they are not strictly identical. Modified GRF(1-29) refers to the unconjugated analogue carrying only the four substitutions. The version sold as CJC-1295 with DAC includes the albumin binding linker and clears much more slowly.