FOXO1 and Glucose intolerance: Alternative explanation is that FoxO1 overexpression in pancreas indeed reduces β cells and causes hyperglycemia in TG mice, but at the same time FoxO1 increases islet vascularities, which could account for the milder reduction of insulin secretion (Fig. 1E) and the milder glucose intolerance (Fig. 1C), in spite of the severe reduction of β cells (Fig. 2A and 2B).