Figure 6. Endogenous OXM signaling regulates food intake-mediated resetting of the liver circadian clock.

(A) Plasma oxyntomodulin-like immunoreactivity (OLI) diurnal profiles under ad libitum food and fasting conditions. Data are presented as mean ± S.E.M (n = 6); factor time F(5, 60) = 0.628, feeding condition F(1, 60) = 15.37, interaction F(5, 60) = 0.638. Grey shading indicates the dark phase. (B) OLI levels show high individual variations in mice after 12 hr of food deprivation (ZT13-1). (C) Plasma OLI (normalized to individual fasting levels) after refeeding (grey line) or under continuous starving (black line); factor time F(3, 21) = 3.544, feeding condition F(1, 21) = 15.82, interaction F(3, 21) = 4.717. (D) Liver Per1/2 induction following fasting-refeeding determined by qPCR; Per1: factor time F(3, 25) = 0.454, feeding condition F(1, 25) = 1.376, interaction F(3, 25) = 4.453; Per2: factor time F(3, 25) = 6.938, feeding condition F(1, 25) = 38.48, interaction F(3, 25) = 3.767. (E) WT and (F) Glp1r^−/− liver Per1/2 expression after fasting-refeeding with control IgG injection (grey) or OXM immuno-neutralization by anti-OXM IgG (aOXM) injection at ZT0; WT: Per1: F(2, 12) = 71.76, Per2: F(2, 12) = 47.41; Glp1r^−/−: Per1 F(2, 12) = 11.51, Per2: F(2, 12) = 5.585. (G–I) Treatment with anti-OXM IgG does not affect postprandial regulation of insulin, GLP-1, and GCG. Plasma levels of insulin (G; F(2, 12) = 17.44), GLP-1 (H; F(2, 12) = 5.563), and GCG (I; F(2, 12) = 7.128) after fasting-refeeding with control IgG injection (grey) or OXM immuno-neutralization by anti-OXM IgG (aOXM) treatment at ZT0. One- (E–I) or two-way ANOVA (A, C, D) with Bonferroni post-test: *p < 0.05; **p < 0.01; ***p < 0.001 against fasted; ##p < 0.01; ###p < 0.001 against IgG. Data are presented as mean ± S.E.M (n = 5). (J and K) Liver PER2::LUC rhythms after fasting-refeeding with control IgG or αOXM administration. (J) Representative luminescence traces. (K) Comparison of phases (second peak in culture) after refeeding and/or anti-OXM treatment (Data are presented as mean ± S.E.M (n = 4 mice per condition, an average of 3 slice preparations of each mouse were used); two-way ANOVA with Bonferroni post-test: *p < 0.05 against fasted; factor treatment F(1, 12) = 5.127, feeding condition F(1, 12) = 13.02, interaction F(1, 12) = 5.044).

DOI: http://dx.doi.org/10.7554/eLife.06253.011

Figure 6—figure supplement 1. Time course of OLI plasma levels after OXM injection.

Time course of OLI appearance in plasma following i.v. (4 μg) or i.p. (25 μg) injections of OXM. OLI plasma level changes are expressed relative to starving levels (0 min) for each individual. Data are presented as mean ± SEM (n = 5). 2-way ANOVA with Bonferroni post-test: ***p < 0.001; factor treatment F(2, 48) = 9.014, feeding condition F(3, 48) = 4.95, interaction F(6, 48) = 5.698.

DOI: http://dx.doi.org/10.7554/eLife.06253.013