The number of GLP-1-positive cells in the frontal cortex is reduced in an obese insulin-resistant mouse model. A. Representative images from the frontal cortex adjacent to the hippocampus of 36-week-old mice showing relative abundance of GLP-1-positive cells (brown) in C57 black control animals (top left panel) —increased magnification (100 X) of GLP-1-positive cells (top right panel) —as compared to obese insulin-resistant ob/ob mice (bottom panel). Scale bar: 80 μm. B. Statistical analysis showing a significant decrease in the number of GLP-1-positive cells/area—in the frontal cortex adjacent to the hippocampus—in obese insulin-resistant ob/ob mice as compared to healthy controls. Data from 4 C57 black mice and 4 ob/ob mice. Bars represent mean ± SEM. * P < 0.05 for a chance difference vs. C57 black mice. Statistical analysis was performed using Mann-Whitney rank sum test.