GPT and metabolic disease: AST and ALT are biomarkers of health and cellular membrane integrity (Costas et al. 2011), indicating liver condition (Ghodrati et al. 2021), signifying metabolic disorders and indications of hepatic injury and failure (Albaqami and Monier 2025; Gao et al. 2022; Guo et al. 2023; Monier et al. 2025).