Fig 7. Phase shift of liver clock, insulin secretion, and clock gene expression in GPR120-deficient mice with tuna oil-containing diet.

GPR120-deficient (KO) and wild-type (WT) mice were fed an AIN-93M diet tablet containing tuna oil at ZT0 for 2 days and bioluminescence rhythm was recorded after sacrifice on Day 3. The horizontal axis indicates projected Zeitgeber time (pZT) at the peak of the bioluminescence rhythm. ZT0 is lights-on time and ZT12 is lights-off time in the housing room prior to sacrifice. (A) de-trended data of expression rhythms of liver PER2::LUCIFERASE bioluminescence in mice under restricted-feeding (RF) of AIN-93M diet containing tuna or soybean oil. The horizontal line indicates time lapse. (B) magnitude of phase-delay by tuna or soybean oil in WT or KO mice. Values are expressed as mean ± SEM. **P < 0.01, (vs. WT SB group, Tukey-Kramer test). (C, D) on Day 2 under RF conditions, mice were fed AIN-93M containing tuna or soybean oil at ZT0, and sacrificed at 120 min to measure insulin and clock gene expression in the liver after feeding. (C) serum insulin levels. Values are expressed as mean ± SEM. *P < 0.05 *** P < 0.001 vs. WT SB group, ## P < 0.01 vs. WT SB (FF) group, Dunn test. (D) Per2 gene expression. The relative levels of expression were normalized to GAPDH. *** P < 0.001 (vs. WT SB group), # P < 0.05 [vs. WT SB (FF) group Dunn test]. SB, soybean; FF, free feeding. Numbers in parentheses indicate the number of tested mice.