Table 2.
Treatmenta |
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---|---|---|---|---|
Hormoneb | Standard Diet/Standard Diet | Standard Diet/high-Protein Diet | Western-Type Diet/Standard Diet | Western-Type Diet/High-Protein Diet |
Amylin | 2.2 ± 0.5 | 3.0 ± 0.4 | 3.8 ± 0.8 | 2.0 ± 0.5# |
GIP | 3.7 ± 0.6 | 4.6 ± 0.5 | 13.1 ± 1.3*+ | 16.3 ± 1.0*+# |
Insulin | 1.1 ± 0.2 | 3.0 ± 0.8* | 2.4 ± 0.4* | 2.1 ± 0.2* |
Leptin | 0.6 ± 0.2 | 0.5 ± 0.1 | 0.5 ± 0.2 | 0.5 ± 0.1 |
PP | 1.0 ± 0.1 | 1.2 ± 0.3 | 2.1 ± 0.6 | 2.3 ± 0.4*+ |
Peptide YY | 1.1 ± 0.2 | 4.0 ± 0.7# | 1.2 ± 0.5 | 2.2 ± 0.3*+ |
After development of diet-induced obesity on a Western-type diet or feeding of a standard diet, rats were fed a standard or high-protein diet for 32 days, resulting in four experimental groups: standard diet/standard diet, standard diet/high-protein diet, Western-type diet/standard diet, and Western-type diet/high-protein diet. 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 p.m. during the light phase (n = 5/group). Afterward, in the remaining rats, food was removed for 2 h. At the beginning of the dark phase at 6 p.m., preweighed rat chow (standard or high-protein diet, respectively) was provided, and rats were left undisturbed for 2 h. After this period, food intake was assessed and rats (n = 5/group) were euthanized to obtain trunk blood, and plasma levels of hormones were assessed.
Data are fold changes of plasma levels from light to the dark phase and expressed as means ± SE. Significant differences are indicated for the change in plasma levels from light to dark phase. GIP, gastric inhibitory polypeptide; PP, pancreatic polypeptide.
P < 0.05 vs. standard diet/standard diet;
P < 0.05 vs. standard diet/high-protein diet; and
P < 0.05 vs. Western-type diet/standard diet.