This is a working overview of Carcinogenicity, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-17 and is reviewed periodically as new material appears.
GW501516 acts as a selective agonist at PPARδ, a nuclear receptor that regulates transcription of genes involved in lipid handling and energy metabolism. Activation of PPARδ in preclinical models increases fatty acid oxidation, mitochondrial biogenesis, and exercise endurance in rodents. These effects have made the compound a subject of metabolic research and also a target for sport anti-doping rules. In humans, however, controlled studies are limited, and whether similar endurance or metabolic changes occur at tolerated exposures remains an open question. The receptor’s broad tissue distribution also means downstream effects may vary by organ and condition.
Detection of GW501516 in biological samples generally relies on liquid chromatography coupled with tandem mass spectrometry. Urine is a common matrix in anti-doping analysis, while blood or plasma may be used in research settings. Sample preparation can involve enzymatic hydrolysis, protein precipitation, or solid-phase extraction before instrumental analysis. Because the compound undergoes metabolism, assays may target the parent molecule, one or more metabolites, or both. Detection windows are not fixed; they depend on factors such as dose, route, individual metabolism, and assay sensitivity. Reference standards are required for accurate identification and quantification.
Laboratory studies indicate that GW501516 activates PPARδ, a nuclear receptor involved in fatty acid oxidation and energy metabolism. In rodent experiments, treated animals often showed increased endurance and reduced fat mass. These effects were observed under controlled conditions and do not establish safe or effective use in humans. The exact dose-response relationship in humans remains poorly characterized. Species differences in metabolism can affect how results translate across animals and people.
Safety concerns emerged from long-term animal studies. In rodents given the compound for extended periods, researchers found an increased incidence of certain cancers, including liver and bladder tumors. These findings contributed to the discontinuation of clinical development. Whether similar risks apply to short-term or low-level exposure in humans is not established, and controlled human safety data are limited. The relevance of high-dose rodent carcinogenicity findings to human use remains a subject of debate.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Visual description for typical solid reference material. |
| Solubility | Poorly soluble in water; soluble in DMSO | Solubility depends on solvent, purity, and form. |
| Storage | Cool, dry, protected from light | Long-term storage often uses low temperature and desiccant. |
| Common analytical method | LC-MS/MS | Used for detection and quantification in biological matrices. |
| Common synonyms | GW-501516; GW501516; endurobol | Naming varies among literature, vendors, and databases. |
Cardarine is a synthetic compound also known as GW501516, GW-501516, and sometimes endurobol. It was developed as a selective agonist of peroxisome proliferator-activated receptor delta, a nuclear receptor involved in fatty acid oxidation and energy metabolism. The compound was studied in preclinical models for metabolic and cardiovascular conditions, but it did not become a marketed human medicine. In regulatory and anti-doping contexts, it is treated as a prohibited substance rather than a licensed medicine.
The pharmacological interest in cardarine centers on PPARδ activation and its downstream effects on lipid handling and mitochondrial function. In animal studies, PPARδ agonists have been associated with changes in exercise endurance and fatty acid utilization, though results vary by model and protocol. Human data remain sparse, and the absence of large controlled trials limits conclusions about efficacy. Researchers often describe the compound as a tool for probing PPARδ biology rather than a proven therapeutic agent.
GW501516 acts as an agonist at the peroxisome proliferator-activated receptor delta, a nuclear receptor that regulates gene expression. Activation shifts transcription toward genes involved in fatty acid uptake, oxidation, and energy expenditure. The compound does not bind the androgen receptor and therefore differs from anabolic steroids and SARMs. In rodent models, this metabolic shift has been linked to increased running endurance and reduced fat accumulation. The exact downstream pathways in humans remain incompletely characterized.
Early clinical research explored GW501516 for lipid disorders, obesity, and diabetes. Some short-term human studies reported changes in HDL cholesterol, LDL cholesterol, and triglycerides. The development program was discontinued after rodent studies showed dose-dependent tumor formation in multiple tissues, including liver, bladder, stomach, and skin. These findings raised concerns about long-term cancer risk in humans. Because human exposure data are limited, the clinical significance of the rodent tumors remains uncertain.
Barbiturate drugs are obtained via condensation reactions between a derivative of diethyl malonate and urea in the presence of a strong base. The synthesis of phenobarbital uses this common approach as well but differs in the way in which this malonate derivative is obtained. The reason for this difference is because aryl halides do not typically undergo nucleophilic substitution in Malonic ester synthesis in the same way as aliphatic organosulfates or halocarbons do. To overcome this lack of chemical reactivity two dominant synthetic approaches using benzyl cyanide as a starting material have been developed: The first of these methods consists of a Pinner reaction of benzyl cyanide, giving phenylacetic acid ethyl ester. Subsequently, this ester undergoes cross Claisen condensation using diethyl oxalate, giving diethyl ester of phenyloxobutandioic acid. Upon heating this intermediate easily loses carbon monoxide, yielding diethyl phenylmalonate. Malonic ester synthesis using ethyl bromide leads to the formation of α-phenyl-α-ethylmalonic ester. Finally, a condensation reaction with urea gives phenobarbital.
If the newborn seems to need help in latching on, the mother should focus on helping the infant by bringing their chin to the breast first. This facilitates a deep, asymmetric latch, and also helps the infant extend their neck and tilt their forehead back to maintain this deep latch and ease the swallowing process.
Neurons that produce GABA as their output are called GABAergic neurons. In adult vertebrates, GABA is usually considered as the major inhibitory neurotransmitter. It also exhibits excitatory effect via GABAB receptor via activation of a specific type of voltage dependent calcium channel. Medium spiny cells are a typical example of inhibitory central nervous system GABAergic cells. In contrast, GABA exhibits both excitatory and inhibitory actions in insects, mediating muscle activation at synapses between nerves and muscle cells, and also the stimulation of certain glands. In mammals, some GABAergic neurons, such as chandelier cells, are also able to excite their glutamatergic counterparts. In addition to fast-acting phasic inhibition, small amounts of extracellular GABA can induce slow timescale tonic inhibition on neurons. GABAA receptors are ligand-activated chloride channels: when activated by GABA, they allow the flow of chloride ions across the membrane of the cell. Whether this chloride flow is depolarizing (makes the voltage across the cell's membrane less negative), shunting (has no effect on the cell's membrane potential), or inhibitory/hyperpolarizing (makes the cell's membrane more negative) depends on the direction of the flow of chloride. When net chloride flows out of the cell, GABA is depolarising; when chloride flows into the cell, GABA is inhibitory or hyperpolarizing. When the net flow of chloride is close to zero, the action of GABA is shunting.
Sources: en.wikipedia.org
While both members bear S-glycosyl groups, RiPPs bearing O- or N-linked carbohydrates will also be included in this family as they are discovered. Linaridins are characterized by C-terminal aminovinyl cysteine residues. While this posttranslational modification is also seen in the lanthipeptides epidermin and mersacidin, linaridins do not have Lan or MeLan residues. In addition, the linaridin moiety is formed from modification of two Cys residues, whereas lanthipeptide aminovinyl cysteines are formed from Cys and dehydroalanine (Dha). The first linaridin to be characterized was cypemycin. Microviridins are cyclic N-acetylated trideca- and tetradecapeptides with ω-ester and/or ω-amide bonds. Lactone formation through glutamate or aspartate ω-carboxy groups and the lysine ε-amino group forms macrocycles in the final natural product. This class of RiPPs function as protease inhibitors and were originally isolated from Microcystis viridis. Gene clusters encoding microviridins have also been identified in genomes across the Bacteroidetes and Proteobacteria phyla. Orbitides are plant-derived N-to-C cyclized peptides with no disulfide bonds. Also referred to as Caryophyllaceae-like homomonocyclopeptides, orbitides are 5-12 amino acids in length and are composed of mainly hydrophobic residues. Similar to the amatoxins and phallotoxins, the gene sequences of orbitides suggest the presence of a C-terminal recognition sequence.
=== Pharmacodynamics === Vilazodone acts as a serotonin reuptake inhibitor (IC50 = 2.1 nM; Ki = 0.1 nM) and 5-HT1A receptor partial agonist (IC50 = 0.2 nM; IA = ~60–70%). It has negligible affinity for other serotonin receptors such as 5-HT1D, 5-HT2A, and 5-HT2C, as well as the norepinephrine and dopamine transporters (Ki = 56 nM for NET and 37 nM for DAT). A small clinical study found occupancy of the 5-HT1A receptor with vilazodone, whereas occupancy of the SERT by vilazodone in humans does not seem to have been studied. It also possesses negligible, if any, clinically relevant affinity for vesicular monoamine transporter 2 (VMAT2) inhibitor (IC50Tooltip half-maximal inhibitory concentration = 69 nM).
==== COVID-19 ==== Use of the intradermal BCG vaccine may provide protection against COVID-19. However, epidemiologic observations in this respect are ambiguous. The WHO does not recommend its use for prevention as of 12 January 2021. As of January 2021, 20 BCG trials are in various clinical stages. As of October 2022, the results are extremely mixed. A 15-month trial involving people thrice-vaccinated over the two years before the pandemic shows positive results in preventing infection in BCG-naive people with type 1 diabetes. On the other hand, a 5-month trial shows that re-vaccinating with BCG does not help prevent infection in healthcare workers. Both of these trials were double-blind randomized controlled trials (RCTs). A 2024 systmatic review of 12 RCTs reports that BCG does not help protect against COVID-19. Follow up of one of the BCG-COVID trials (BATTLE) shows positive results in preventing long COVID.
Sources: en.wikipedia.org
Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.
Most methods use liquid chromatography with tandem mass spectrometry. Urine is common in anti-doping testing, and blood or plasma may be used in research.
Typical guidance is cool, dry, dark storage, often at low temperature and with desiccant. Stability data are limited, so storage conditions should be verified for each batch or supplier.
Rodent studies reported increased endurance and fat oxidation after GW501516 exposure. Long-term studies also found higher rates of some tumors, which led to halted development.