GPT and metabolic dysfunction-associated steatohepatitis: Moreover, NASH diet–fed mice had significantly elevated serum alanine transaminase (ALT) levels (129 ± 16 versus 24 ± 4 U/L in RC control, P < 0.001) (Supplemental Table 1), correlating with the development of hepatic inflammation, steatosis, and fibrosis in NASH diet–fed mice.