Apelin
Endogenous Cardiovascular/Metabolic PeptideresearchAlso known as: Apelin-13, Apelin-36, APLN, Apelin Peptide
An endogenous peptide ligand for the APJ receptor involved in cardiovascular regulation, fluid homeostasis, angiogenesis, and energy metabolism, with therapeutic potential for heart failure.
Overview
Apelin is an endogenous peptide first identified in 1998 as the ligand for the previously orphan APJ receptor (now APLNR). It exists in multiple isoforms (apelin-36, apelin-17, apelin-13, and pyroglutamated apelin-13), all derived from a 77-amino acid preproprotein. Apelin is widely expressed in the heart, vasculature, brain, adipose tissue, and GI tract. It is one of the most potent endogenous inotropic peptides, increasing cardiac contractility without hypertrophy. Apelin causes vasodilation via endothelial nitric oxide release, opposes the vasoconstrictive effects of angiotensin II, promotes angiogenesis, and enhances glucose utilization. Apelin levels are altered in heart failure, obesity, and diabetes, making it an active area of therapeutic research. Synthetic apelin analogs are in clinical development for heart failure and pulmonary arterial hypertension.
Mechanism of Action
Apelin signals through the APJ (APLNR) receptor: (1) Increases cardiac contractility (positive inotropy) via phospholipase C and PKC activation without causing hypertrophy; (2) Causes endothelium-dependent vasodilation through NO and prostacyclin release; (3) Reduces cardiac preload and afterload; (4) Opposes the RAAS by counteracting angiotensin II effects and suppressing vasopressin release; (5) Promotes angiogenesis during development and ischemic conditions; (6) Enhances glucose uptake in skeletal muscle via AMPK activation; (7) Modulates fluid homeostasis by opposing ADH-mediated water reabsorption in the kidney.
Molecular Formula
C65H92N18O14S (apelin-13: pGlu-Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Met-Pro-Phe)
Molecular Weight
1550.67 g/mol (apelin-13)
Sequence
[Pyr]-Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Met-Pro-Phe (pyroglutamated apelin-13)
Dosage Protocols
Dose Range
10 nmol/min – 135 nmol/min
Frequency
IV infusion (research)
Route
intravenous
Cycle Length
Acute dosing studies
Human studies have used IV apelin infusions to assess hemodynamic effects. No approved dosing exists. Rapid degradation limits utility of native peptide; stabilized analogs are in development.
Source: Clinical research studies
🧮 Personalized Dosage Calculator
💰 Estimated Pricing
Typical Supply
1mg vial
Last Updated
2026-02
Cardiovascular research peptide. Very limited commercial availability. Academic/research suppliers only.
⚠️ Prices are estimates based on publicly available data and may vary significantly by vendor, location, and prescription status. This is not medical or financial advice.
Side Effects
| Effect | Severity |
|---|---|
| Hypotension | moderate |
| Flushing | mild |
| Tachycardia | mild |
Pros & Cons
One of the most potent endogenous positive inotropes — increases cardiac output without hypertrophy
Counteracts harmful RAAS activation, offering a novel approach to heart failure
Dual cardiovascular and metabolic benefits (vasodilation + glucose uptake enhancement)
Extremely short half-life (<5 minutes) of native peptide limits clinical utility
No approved formulations; still in early clinical development
Complex physiology — effects vary by isoform, tissue, and disease state
Research Studies
🩸 Blood Work
No specific bloodwork requirements reported for this peptide. General health panels are always recommended before starting any peptide protocol.
Legal Status
Endogenous peptide available as research reagent. No approved therapeutic formulations. Synthetic apelin analogs (e.g., MM07, BMS-986224) are in clinical trials for heart failure and PAH.
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