FIG. 3.

Data from 120-min insulin-induced hypoglycemic clamp experiments in 5-h-fasted, surgically catheterized C57BL/6 (BL6; n = 8), 129X1/Sv (129; n = 9), FVB/N (FVB; n = 9), and DBA/2 (DBA; n = 10) male mice. Insulin was infused at t = 0 min at 120 pmol · kg⁻¹ · min⁻¹, and whole-blood glucose (A; mmol · l⁻¹) was maintained at ∼3.0 using a variable GIR (B; mmol · kg⁻¹ · min⁻¹). Inset in B depicts the glucose AUC during the 120-min experimental period determined by the trapezoidal method. The hypoglycemic counter-regulatory response was assessed by determining glucagon (C; ng/l), corticosterone (D; ng/l), epinephrine (F; pmol/l), and norepinephrine (G; nmol/l) at t = 0 (basal), 30, 60, and 120 min. Epinephrine levels in 129X1/Sv mice were below detection at all time points and were excluded from F. All values are means ± SE, and comparisons are ^AC57BL/6 versus 129X1/Sv, ^BC57BL/6 versus FVB/N, ^CC57BL/6 versus DBA/2, ^D129X1/Sv versus FVB/N, ^E129X1/Sv versus DBA/2, and ^FFVB/N versus DBA/2, where statistical significance is established at P < 0.05 and differences are noted above each time point for clarity.