Fig. 7.

Changes in intestinal hormones after 2-h dark phase feeding compared with the preprandial light phase. After development of diet-induced obesity on Western-type diet or feeding of standard diet, rats were fed a standard or high-protein diet for 32 days, resulting in four experimental groups: standard diet/standard diet (SD/SD), standard diet/high-protein diet (SD/HPD), Western-type diet/standard diet (WTD/SD), and Western-type diet/high-protein diet (WTD/HPD). The four groups fed ad libitum with standard or high-protein diet, respectively, were euthanized by decapitation to obtain trunk blood between 3 and 4 PM during the light phase. The remaining rats were euthanized after a 2-h dark phase feeding period, trunk blood was collected, and the plasma levels of amylin (A), gastric inhibitory polypeptide (GIP; B), insulin (C), leptin (D), pancreatic polypeptide (PP; E), and peptide YY (PYY; F) were assessed. Data are expressed as mean ± SE of 5 rats/group. *P < 0.05, **P < 0.01, and ***P < 0.001 vs. same diet group during light phase; #P < 0.05 and ##P < 0.01 vs. standard diet/standard diet group during same photoperiod.