In contrast, the mRNA expression of cholesterol 7α-hydroxylase (Cyp7a1, the rate-limiting enzyme in bile acid metabolism) had increased significantly in the lean hamsters by dpi 25 (and, to a lesser extent, by dpi 7) but remained constant in obese NASH hamsters (Figure 5B). Here, CYP7A1 is linked to metabolic dysfunction-associated steatohepatitis.