Activin Type IIB Receptor (ActRIIB)
Definition
The receptor through which myostatin and related TGF-beta ligands signal to limit skeletal muscle mass. Decoy receptors and antibodies aimed at it are the main pharmacological route to inhibiting that signal.
What this means for research sourcing
Mechanistic terms like this describe how research compounds behave in vitro. See the mechanism overviews for compounds Volta stocks.
Related Terms in Pharmacology
Senolytic
A compound meant to clear senescent cells selectively while leaving dividing ones alone. FOXO4-DRI is the peptide studied this way, in cell and animal models, and human data for the approach is minimal.
Senescent Cells
Cells that have stopped dividing for good but resist apoptosis and persist, secreting inflammatory mediators as they go. They accumulate with age and their secretions degrade the tissue around them.
SASP (Senescence-Associated Secretory Phenotype)
The mixture of cytokines, chemokines, growth factors and proteases that senescent cells release. It is the reason a non-dividing cell is a problem rather than merely inert, and clearing the cells that produce it is the senolytic premise.
Sirtuin
A family of NAD-dependent enzymes that modify proteins involved in metabolism, DNA repair and stress response. They are the usual mechanistic hook for claims made about NAD precursors.
NAD+ (Nicotinamide Adenine Dinucleotide)
The central redox cofactor in every living cell, carrying electrons through energy metabolism and acting as a substrate for the sirtuins and PARP enzymes. It is a nucleotide rather than a peptide, and it is grouped with research peptides for commercial reasons rather than chemical ones.
Telomerase
The enzyme that rebuilds telomeres and so offsets the shortening that comes with each division. Epithalon is studied for effects on its activity, with human cell-culture work from Khavinson and colleagues in 2003, rodent studies and Russian clinical reports, and no Western randomised trial.
IC50
The concentration producing half of the maximum inhibition in a given assay. It is assay-dependent rather than a constant of the compound, so IC50 values are comparable only when the conditions behind them are.
Dissociation Constant (Kd)
The concentration at which half the available binding sites are occupied at equilibrium. A lower value means tighter binding, and unlike IC50 it describes the interaction rather than the readout used to measure it.