MBP and diabetes mellitus: After nephrectomy of the kidney containing β-cell spheroids, the blood glucose levels in both RBP and MBP-FGF2 groups were elevated to a hyperglycemic condition, indicating that the regulation of blood glucose levels in mice with STZ-induced diabetes was indeed regulated by the transplanted β-cell spheroids in both the RBP and MBP-FGF2 groups (Fig. 5C).