Mod GRF(1-29) raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-06-26. 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.
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.
| 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 |
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.
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.
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.
CJC-1295 belongs to a class of synthetic peptides modeled on growth hormone releasing hormone, a forty-four amino acid signal produced by the hypothalamus. The compound is built from the first twenty-nine residues of the natural sequence, with four substitutions introduced at positions 2, 8, 15 and 27. These changes were designed to slow enzymatic breakdown while preserving receptor activation. The result is a peptide that is shorter than native GHRH and considerably more resistant to ordinary clearance pathways in circulation.
Eine Vielzahl von Arzneimitteln kann zur Kristallen im Urin führen, insbesondere bei Überdosierung, rascher intravenöser Gabe, Albuminmangel, Austrocknung und in Abhängigkeit vom Urin-pH: Sulfadiazin, Aciclovir, Indinavir, Pyridoxylat, Primidon, Felbamat, Amoxicillin und Ciprofloxacin. Bestimmte Medikamente können auch zu einer vermehrten Ausscheidung von Calcium-Oxalat-Kristallen führen, z. B. Naftidrofuryloxalat, Vitamin C und Orlistat.
== Literatur == Erich Ebstein: Zur Entwicklung der klinischen Harndiagnostik in chemischer und mikroskopischer Hinsicht. Leipzig 1915. Franz Fischler, Ferdinand Schlemmer: Anleitung zur Harnuntersuchung. 5., verbesserte Auflage (Neubearbeitung von Ferdinand Schlemmer und Heinrich Thies). Verlag J. F. Bergmann, München 1966. Giovanni B. Fogazzi et al.: Urinalysis: Core Curriculum 2008. In: American Journal of Kidney Diseases. Vol. 51, Issue 6, 2008, S. 1052–1067 (Artikel). Giovanni B. Fogazzi, Milan, Italy: Bedside urinary microscopy. Urinary Sediment Part 1: Methods, Part 2: Particles I, Part 3: Particles II, Part 4: Clinical practice I, Part 5: Clinical practice II, Part 6 and last: Contaminants and funny findings. Hands on course der European Dialysis and Transplantation Organisation. Lothar Thomas: Labor und Diagnose. 7. Auflage (November) 2007, Th-Books, ISBN 978-3-9805215-6-7.
2,3,7,8-Tetrachlordibenzodioxin ist eine chlorhaltige, hochgiftige organische Verbindung. Der systematische Name lautet 2,3,7,8-Tetrachlordibenzo-p-dioxin bzw. 2,3,7,8-Tetrachlordibenzo-1,4-dioxin (gesprochen zwei- drei- sieben- acht- tetrachlor- dibenzo- para- di-oxin). Die Verbindung leitet sich vom Dibenzodioxin ab und wird abgekürzt als 2,3,7,8-TCDD oder nur TCDD, umgangssprachlich häufig auch (fälschlich) als Dioxin oder als Seveso-Dioxin bzw. Seveso-Gift bezeichnet. Der Kurzname Dioxin bezeichnet vielfach unspezifisch die gesamte übergeordnete Stoffgruppe der polychlorierten Dioxine und Dibenzofurane, deren giftigster Vertreter das 2,3,7,8-Tetrachlordibenzodioxin ist. TCDD kann als unerwünschtes Nebenprodukt bei der Herstellung der wirtschaftlich sehr bedeutsamen chlororganischen Verbindungen (Chlorchemie) und bei der Verbrennung ähnlicher Stoffe entstehen. Typische Konzentrationen liegen dabei im ppm-Bereich, bei vereinzelten schweren Chemie-Unfällen wie dem italienischen Sevesounglück von 1976 entstanden Mengen bis in den Kilogramm-Bereich. TCDD kann in Spuren auch bei Waldbränden entstehen, andere Quellen sind Motorenabgase, Zigarettenrauch, Feuerwerk sowie generell Schwelbrandprozesse bei niederen Temperaturen. Die Verbindung ist ein Gift- bzw. Schadstoff und besitzt keinerlei technischen oder wirtschaftlichen Nutzwert. Analytische Standardverfahren zur Detektierung und Bewertung von polyhalogenierten Dibenzodioxinen und -furanen wurden maßgeblich von Karlheinz Ballschmiter ausgearbeitet.
== Geschichte == TCDD wurde erstmals 1957 von Wilhelm Sandermann im Labor synthetisiert. Er entdeckte auch die Wirkung von TCDD. Schon im November 1953 war es bei der BASF bei der Chlorierung von Diphenyloxiden zu einem Unfall gekommen, in dessen Folge mehrere Arbeiter an schwerer Chlorakne erkrankten. Ähnliche Fälle ereigneten sich bereits 6 Jahre zuvor in den USA sowie 1952, 1954 und 1956 bei der Firma Boehringer Ingelheim. Im Vietnamkrieg wurde von 1965 bis 1970 das Entlaubungsmittel Agent Orange eingesetzt, dessen Verunreinigung mit TCDD zu schweren, bis heute andauernden Schädigungen bei Bevölkerung und US-Soldaten führte. Am 10. Juli 1976 kam es zu dem verheerenden Sevesounglück, bei dem in der norditalienischen Stadt Seveso zwischen einigen hundert Gramm und wenigen Kilogramm an TCDD austraten. Im Laufe der Präsidentschaftswahlen in der Ukraine 2004 bestätigte sich der Verdacht auf eine Dioxinvergiftung des Kandidaten Wiktor Juschtschenko, als seine Ärzte in seinem Blut und Gewebe mehr als das 50.000fache der normalen Konzentration an TCDD fanden. Juschtschenkos Gesicht zeigt seit dem Anschlag starke Chlorakne-Symptome.
Sources: de.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.
Chromatography reports how much material elutes as a single peak but does not confirm what that material is. Mass spectrometry supplies the molecular mass, which is characteristic of a given sequence and its modifications. Together the two methods support both a purity figure and an identity claim.