Dysregulation of glutamine metabolism is dynamic and reversible in liver fibrosis. Mice were treated with chow diet or MCDE diet for 3 weeks. The MCDE diet was removed in some mice for 3 weeks after 3 weeks of treatment. (A) mRNA of Slc1a5, Gls1, and Gls2 was measured by reverse-transcription polymerase chain reaction. Bars represent means ± SEM of n = 3 mice/group. *P < .05 vs chow diet; #P < .05 vs MCDE group. (B) Protein expression of Gls1 (both variants: KGA and GAC), GS, and Gls2 was measured by Western blot. (C) Representative IHC staining of Gls1 in mice treated with chow or MCDE diet for 3 weeks. Red arrows indicate positively stained cells. (D) Representative IHC staining of GS and Gls2 in mice treated with chow or MCDE diet for 3 weeks. (E) mRNA expression was measured by reverse-transcription polymerase chain reaction in freshly isolated primary mouse hepatocytes and hepatic stellate cells. Bars represent means ± SEM of n = 3–4 assays. *P < .05 vs hepatocyte. GAC, Glutaminase C; KGA, kidney-type glutaminase; pHep, primary hepatocyte; pHSC, primary hepatic stellate cell.