Notes from the literature.

These articles summarize published research for scientific reference only. They are not medical advice and do not describe, recommend or endorse use in humans or animals. Some compounds discussed are not supplied by Ri18 Labs. Materials we do supply are for in-vitro laboratory research only.

• Metabolism

  ATX-304 (O304): what preclinical work shows about pan-AMPK activation

  ATX-304, first described as O304, is a small-molecule activator of AMP-activated protein kinase (AMPK). Mouse studies have used it to probe how sustained AMPK activity shapes glucose handling, muscle energetics and microvascular blood flow.

  Mouse · Cell culture · 2 min read · October 28, 2026

• Tissue biology

  ARA-290 (cibinetide): EPO-derived signaling without erythropoiesis

  ARA-290 is an 11-amino-acid peptide modeled on one face of erythropoietin (EPO). It was designed to separate EPO’s non-erythropoietic signaling from its effect on red blood cell production. Most of its mechanistic characterization comes from rodent nerve-injury and inflammation models.

  Rat · Mouse · Cell culture · 2 min read · October 27, 2026

• Neuroscience

  P021: a CNTF-derived peptide studied in Alzheimer’s mouse models

  P021 (often written P21) is a small peptidomimetic derived from ciliary neurotrophic factor (CNTF), modified with an adamantane group for stability. In rodent studies it has been associated with increased neurogenesis, BDNF expression and reduced tau pathology.

  Transgenic mouse · Rat · 2 min read · October 26, 2026

• Tissue biology

  BPC-157 in rodent tendon and gastrointestinal models

  BPC-157 is a 15-amino-acid sequence derived from a protein found in gastric juice. Rodent and cell-culture studies have examined it in tendon, ligament and gastrointestinal injury models, with reported effects on fibroblast migration and angiogenic signaling.

  Rat · Cell culture · 1 min read · October 24, 2026

• Tissue biology

  Thymosin β4 in mouse cardiac injury models

  Thymosin β4 is a 43-amino-acid actin-sequestering protein. Two landmark mouse studies in Nature linked it to cardiomyocyte survival and to the activation of epicardial progenitor cells after injury. “TB-500” usually refers to a synthetic peptide based on its actin-binding region.

  Mouse · Cell culture · 1 min read · October 22, 2026

• Tissue biology

  GHK-Cu: fifty years of copper-peptide research

  GHK (glycyl-L-histidyl-L-lysine) is a tripeptide first isolated from human plasma in 1973 that binds copper(II) with high affinity. Cell-culture studies associate the copper complex with collagen and glycosaminoglycan synthesis in fibroblasts, and gene-expression analyses have linked it to broad changes in transcription.

  Cell culture · Rodent · 2 min read · October 20, 2026

• Mitochondria

  MOTS-c: a peptide encoded in mitochondrial DNA

  MOTS-c is a 16-amino-acid peptide encoded within the mitochondrial 12S rRNA gene. Cell and mouse studies link it to the folate cycle, AMPK activation and skeletal-muscle metabolism, and show it can move to the nucleus under metabolic stress.

  Mouse · Cell culture · 2 min read · October 18, 2026

• Mitochondria

  Humanin: the first mitochondrial-derived peptide

  Humanin was discovered in 2001 in a screen for factors that protect neurons from Alzheimer’s-associated toxicity. Encoded within mitochondrial 16S rRNA, it has since been studied as a cytoprotective signal acting through both intracellular partners and cell-surface receptors.

  Cell culture · Mouse · 1 min read · October 16, 2026

• Mitochondria

  SS-31: a cardiolipin-targeted peptide in mitochondrial research

  SS-31 is a cell-permeable tetrapeptide that concentrates at the inner mitochondrial membrane and binds cardiolipin. Studies in isolated mitochondria and in mice have made it a widely used tool for studying mitochondrial bioenergetics and cardiolipin.

  Mouse · Isolated mitochondria · 1 min read · October 14, 2026

• Senescence biology

  FOXO4-DRI: a peptide approach to clearing senescent cells

  FOXO4-DRI is a D-retro-inverso peptide designed to disrupt the interaction between FOXO4 and p53 in senescent cells. In a 2017 Cell paper it selectively triggered apoptosis of senescent cells in culture and was studied in fast-ageing and naturally aged mice.

  Mouse · Cell culture · 1 min read · October 12, 2026

• Senescence biology

  Epitalon and telomerase activity in cultured cells

  Epitalon (Ala-Glu-Asp-Gly) is a synthetic tetrapeptide modeled on a pineal gland extract. Reports from St Petersburg describe telomerase induction and telomere elongation in cultured human fibroblasts, but the work has seen little independent replication.

  Cell culture · Rodent · 1 min read · October 10, 2026

• Immunology

  KPV: an α-MSH-derived tripeptide in intestinal inflammation models

  KPV (Lys-Pro-Val) is the C-terminal tripeptide of α-melanocyte-stimulating hormone. Mouse colitis studies show it is taken up by intestinal epithelial cells through the PepT1 transporter and reduces NF-κB-driven inflammatory signaling.

  Mouse · Cell culture · 1 min read · October 8, 2026

• Immunology

  LL-37: the human cathelicidin and biofilm research

  LL-37 is the only human cathelicidin antimicrobial peptide. Beyond killing bacteria by disrupting membranes, it modulates immune signaling and, at sub-lethal concentrations, prevents biofilm formation by Pseudomonas aeruginosa in vitro.

  Cell culture · Bacterial culture · 1 min read · October 6, 2026

• Neuroscience

  Dihexa: an angiotensin IV analog acting on the HGF/c-Met system

  Dihexa is a metabolically stabilized derivative of angiotensin IV developed at Washington State University. It has been studied in rat scopolamine models of spatial learning, and its synaptogenic effects in culture depend on hepatocyte growth factor (HGF) and its receptor c-Met.

  Rat · Cell culture · 1 min read · October 4, 2026

• Neuroscience

  Semax and Selank: short regulatory peptides in rodent neuroscience

  Semax and Selank are heptapeptides developed in Russia from ACTH(4–10) and tuftsin respectively, each extended with a stabilizing Pro-Gly-Pro tail. Rodent studies report changes in BDNF expression (Semax) and in anxiety-related behavior and monoamine signaling (Selank).

  Rat · 1 min read · October 2, 2026

• Endocrinology

  Kisspeptin and the GnRH pulse generator

  Kisspeptins are peptides from the KISS1 gene that act on the receptor KISS1R (GPR54). Since 2003 they have been recognized as essential upstream regulators of gonadotropin-releasing hormone (GnRH) neurons. They are now central tools for studying how the brain times reproductive hormone pulses.

  Mouse · Sheep · Genetics · 1 min read · September 30, 2026

• Methods

  Glutathione in redox research: measuring GSH and GSSG reliably

  Glutathione (γ-glutamyl-cysteinyl-glycine) is the most abundant low-molecular-weight thiol in mammalian cells. Its ratio of reduced (GSH) to oxidized (GSSG) form is a common redox readout, but it is easy to measure wrongly. This article reviews the main assay pitfalls.

  Cell culture · Tissue extracts · 1 min read · September 28, 2026

• Endocrinology

  CJC-1295 and ipamorelin as tools for studying the GH axis

  CJC-1295 is a GHRH analog designed to bind serum albumin, and ipamorelin is a selective agonist of the ghrelin receptor (GHS-R1a). Preclinical work uses them to separate the two main stimulatory inputs to pituitary growth-hormone release.

  Mouse · Rat · Pituitary cell culture · 1 min read · September 26, 2026

• Immunology

  Thymosin α1 and innate immune signaling in dendritic cells

  Thymosin α1 is a 28-amino-acid peptide derived from prothymosin α, first isolated from thymus extracts. Mouse and cell studies show it acts on dendritic cells through Toll-like receptor signaling, shaping T-helper responses to fungal and viral challenges.

  Mouse · Cell culture · 1 min read · September 24, 2026

• Methods

  Making peptides last: stapling, cyclization and D-amino acids

  Short linear peptides are often unstructured and quickly broken down by proteases, which limits their use as research tools. Hydrocarbon stapling, cyclization, D-amino-acid substitution and retro-inverso design are the main ways chemists stabilize them. This article outlines how each works.

  Chemistry · Cell culture · Mouse · 2 min read · September 22, 2026