Fig. 4.

(A) Comparison of blood glucose levels in glucagon receptor null (Gcgr^−/−) mice (□) and wild-type (Gcgr^+/+) controls (•) after treatment with double-dose alloxan. (B) Comparison of severity of insulin deficiency in the alloxan-treated Gcgr^−/− and Gcgr^+/+ and nondiabetic Gcgr^−/− and Gcgr^+/+ controls based on plasma insulin levels and morphometric values for insulin-immunostained β-cells in pancreata. The results indicate no significant difference in residual insulin that could explain the absence of hyperglycemia in the alloxan-treated Gcgr^−/− group. Nondiabetic, □; alloxan diabetic, ■.