Alanine aminotransferase (ALT) (ALT)

Alanine aminotransferase (ALT), also known as glutamate pyruvate transaminase (GPT), is a pyridoxal phosphate-dependent enzyme primarily localized in the cytosol of hepatocytes, with lower concentrations found in the kidneys, heart, and skeletal muscles [StatPearls; Wikipedia]. It plays a fundamental role in amino acid metabolism by catalyzing the reversible transamination of L-alanine and alpha-ketoglutarate into pyruvate and L-glutamate, which are critical precursors for the glucose-alanine cycle and gluconeogenesis [Int. J. Health & Med. Res., 2024; Mayo Clinic]. Although ALT is not a primary therapeutic target for direct pharmacological inhibition, its serum levels are the gold-standard biomarker for detecting and monitoring hepatocellular injury in clinical practice [Pfizer; PubMed: 36245342]. When liver cell membrane integrity is compromised by viral hepatitis, metabolic stress, or toxins, the enzyme leaks into the systemic circulation, making elevated ALT a sensitive indicator of liver diseases such as non-alcoholic steatohepatitis (NASH) and drug-induced liver injury (DILI) [StatPearls; NIH/LiverTox]. Consequently, regular monitoring of ALT levels is a mandatory safety component in drug development and clinical diagnostics to evaluate the hepatotoxic risk of experimental and approved medications [Pfizer; NIH/LiverTox].

Other names

Glutamate pyruvate transaminaseGPTAlanine transaminaseSerum glutamic-pyruvic transaminaseSGPTALATAlanine aminotransferase 1

Alanine aminotransferase is not typically a direct therapeutic target; however, its serum levels serve as a primary clinical biomarker for diagnosing hepatocellular injury and monitoring the safety and efficacy of treatments for liver and metabolic diseases [StatPearls; Pfizer].