Rat Serum Albumin (RSA) (RSA)

Rat Serum Albumin (RSA) is the most abundant protein in rat plasma, synthesized primarily by hepatocytes and secreted into the bloodstream (UniProt P02770). It is a single-chain globular protein that plays a fundamental role in maintaining the colloid osmotic pressure of the blood, which is essential for proper fluid distribution between the intravascular and extravascular compartments (NCBI Gene 24186). Beyond its osmotic function, RSA acts as a major transport protein, binding and carrying a wide array of endogenous ligands including long-chain fatty acids, bile salts, bilirubin, and various hormones (Peters, 1996). In the context of pharmacology, RSA is a critical determinant of drug pharmacokinetics, as many therapeutic compounds bind reversibly to its specific hydrophobic pockets, such as Sudlow's sites I and II. This binding influences the free fraction of the drug available for therapeutic action and metabolism, making RSA a key factor in preclinical drug development and toxicology studies. While RSA is not a traditional therapeutic target for disease modulation, it is frequently utilized in drug delivery systems to improve the solubility and half-life of hydrophobic drugs. Pathologically, alterations in RSA levels serve as important biomarkers for liver dysfunction, kidney disease (e.g., nephrotic syndrome), and systemic inflammation in laboratory rat models. Understanding the structural and functional differences between RSA and human serum albumin is vital for accurately extrapolating preclinical data to human clinical trials (Kragh-Hansen et al., 2002).

Other names

AlbuminSerum albuminAlbALBU_RAT

Rat Serum Albumin facilitates the systemic distribution of poorly soluble compounds by providing reversible binding sites, primarily Sudlow's sites I and II, which regulate the free fraction of drugs in the circulation and influence their metabolic clearance and half-life.