GPT and metabolic disease: The serum levels of the liver enzymes alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) are markers of hepatocyte function [7] and elevated in various liver dysfunctions like nonalcoholic fatty liver disease (NAFLD) [4] as well as other metabolic disorders [8].