GPT and metabolic dysfunction-associated steatohepatitis: Thus, the most likely explanation for almost equal serum bilirubin concentrations in NASH patients and control subjects is the latent-to-apparent liver damage (as evidenced by increased ALT activities (Table 1)), and the dysregulated oxidative stress defense (as evidenced by increased GGT activities (Table 1)) of the liver parenchyma in NASH patients that is accompanied with impaired hepatic bilirubin metabolism and a mild elevation of serum bilirubin concentrations (Table 1 and Table 2).