Figure 1. The effect of glucose signal on the phosphorylation level of AMPK and the expressions of the incretin receptors in mouse islets.

A), B) Isolated islets were incubated for 24 h in the presence of 2.8, 5.6, 11.1 or 22.2 mM glucose. A) Total cell extracts from the isolated islets were subjected to immunoblotting for p-AMPKα (Thr¹⁷²) and AMPKα. Data shown are representative of three independent experiments. B) The GLP-1 and GIP receptor expressions in the islets were determined by real-time quantitative RT-PCR and normalized to the expression level of β actin mRNA and to the samples at 2.8 mM glucose (n = 4). The samples are from independent experiments. *P<0.05 and ** P<0.01. C) Isolated islets were incubated for the indicated times in the presence of 2.8, 11.1 or 22.2 mM glucose. The GLP-1 and GIP receptor expressions were determined as shown in B. (n = 4). The samples are from independent experiments. * P<0.05 and ** P<0.01 vs. 2.8 mM glucose. ^† P<0.05 and ^†† P<0.01 vs. 22.2 mM glucose.