Fig. 4.

Leptin treatment reverses dysregulation of ob/ob islets. (A) Longitudinal in vivo imaging of islet grafts in ob/ob mice receiving leptin treatment (Upper) or sham treatment (Lower) between 3 and 4 mo of age. Vasculature was visualized by tail vein injection of dextran-FITC. (B) Islet volume analysis showing reversal of islet growth during leptin treatment (gray bars) compared with sham treatment (white bars). There was no difference in islet growth after the end of leptin or sham treatment. (C) Immunohistochemistry analysis of transplanted eye and pancreas samples from ob/ob mice at the end of the leptin treatment demonstrating the attenuated beta cell proliferation by immunostaining for insulin and Ki67 (compare with Fig. 2F). Confocal images are representative and shown as MIPs. Values are average ± SEM. ***P < 0.001. (Scale bars: 100 µm.)