Figure 6. AMPK is involved in glucose enhancement of leptin signaling.

A, γ2A^LEPRb/JAK2 cells were deprived of serum overnight (in 25 mM glucose). Cells were treated with 25 mM 2-DG or 2 mM AICAR for 3 h, and then with 100 ng/ml leptin for additional 10 min. Cell extracts were immunoblotted with the indicated antibodies. B, PC12^LEPRb neurons were deprived of serum overnight in the presence of 25 mM glucose, and treated with 25 mM 2-DG or 2 mM AICAR for 1 h and then with 100 ng/ml leptin for additional 10 min. Cell extracts were immunoblotted with the indicated antibodies. C, PC12^LEPRb neurons were incubated overnight (∼15 h) in the presence or absence of 40 µM compound C. Some cells were pretreated with 2-DG (25 mM) for 1 h as indicated. Cells were stimulated with 100 ng/ml leptin for 10 min, and cell extracts were immunoblotted with the indicated antibodies.