FIGURE 1.

Effects of fasting on TG content in livers of various inbred strains of mice. A, family tree of inbred mouse strains (15). The 7 strains studied in this report are denoted by the following colors: black, C57BL/6J; red, SJL/J; and blue, 5 other strains. One additional strain previously reported to manifest fasting-induced fatty liver (7) is denoted in green. (B–E), different strains of male mice (9–12 weeks of age) were fed a chow diet ad libitum (fed) or fasted for 24 h prior to study. B, liver TG content was determined by extraction and enzymatic assay. C and D, serum levels of free FA (C) and ketone bodies (D) from fed or fasted animals were determined by enzymatic assays. B–D, each bar represents the mean ± S.E. of values from six mice except for SJL/Bm (n = 4). Asterisks denote the level of statistical significance (Student's t test) between the fed and fasted mice in each strain. *, p < 0.05; **, p < 0.01; ***, p < 0.001. E, oil red O-stained histological sections of livers from fed (left) and fasted (right) C57BL/6J (top) and SJL/J (bottom) mice. Animals were perfused with Hank's Balanced Salt Solution and then with 10% (v/v) formalin in PBS through the heart; frozen sections of livers were stained with oil red O. Magnification, ×20.