FIGURE 7.

Increased hepatic AMPK activity in adPPARδ mice. A, Western blot analyses showing increased phospho-AMPK (p-AMPK, Thr-172) in adPPARδ livers. Liver lysates were collected from four individual GFP or adPPARδ mice. B, adenine nucleotide concentrations of liver lysates from control or adPPARδ mice (n = 4) determined by HPLC assays. *, p < 0.05; +, p = 0.08. C, real time qPCR analyses demonstrating up-regulation of adiponectin receptor 2 (AdipoR2) in adPPARδ livers. The difference in adiponectin receptor 1 (AdipoR1) expression was not significant. D, circulating adiponectin concentrations in control (GFP) and adPPARδ mice determined by ELISA. E and F, PPARδ expression increases AMPK phosphorylation. Hepatocytes were infected with GFP or PPARδ virus for 24 h in William's E, 5% FBS. The cells were washed and cultured in DMEM for 2 h. In E, hepatocytes were incubated in DMEM for 4 more hours before harvesting. The results from two representative samples were shown. In F, hepatocytes were treated with metformin (met, 2 mm) and harvested at different time points. The basal phospho-AMPK was higher at 6 h (E) than at 3 h (F, minus metformin) after replacing medium to DMEM in PPARδ-expressing hepatocytes. G, PPARδ reduces glucose production through AMPK activation in primary hepatocytes. Hepatocytes were treated as described above. The cells were then cultured in glucose free DMEM containing 1 mm pyruvate and 10 mm lactate, without or with 20 μm compound C (AMPK inhibitor, AMPKi) or 2 mm metformin (AMPK activator) for 2 h. Supernatant was collected to determine glucose concentration. Metformin was included as a control for AMPK-mediated suppression of glucose production. *, p < 0.05.