Fig. 2.

Elevation of serum transaminases, insulin resistance, and onset of steatosis occurs rapidly in FF mice (n = 8–10 samples all groups and time points). A: serum AST levels increased by 1 wk, normalized to baseline by 4 wk, and increased sharply thereafter. AST levels in SC mice were also increased over baseline. B: insulin resistance [homeostasis model assessment-insulin resistance (HOMA-IR)] increased by 1 wk, normalized to baseline by 4 wk, and increased sharply thereafter. SC mice showed a marginal increase in HOMA-IR over baseline. C: hematoxylin and eosin sections of mice reared on FF demonstrate rapid onset of steatosis over time. Hepatic fat accumulation was largely microvesicular at earlier time points of 1 to 4 wk and macrovesicular thereafter. Inflammatory infiltrates are visible as early as 1 wk (black arrows). No ballooning was observed. D: histological scoring for steatosis indicate that maximum scores were attained by 4 wk, which persisted throughout the experimental period. By comparison, SC mice attained a minimal score of 0.45 ± 0.18 by 36 wk (magnification, ×200). *P < 0.05; ***P < 0.001.