Extended Data Fig. 7: Glucagon receptor blockade prevents hypoglycaemia-associated changes in counter-regulatory glucagon responses.
a, Plasma glucose levels after administration of saline (‘control’, black), insulin (‘hypo’, red) or the combination of insulin and Gcg-amide (1 mg/kg; ‘hypo + Gcg-amide’, blue) on Day 0 (5 mice/group). **p = 0.009, ***p = 0.0005, ****p < 0.0001 vs. control; #p = 0.04, ##p = 0.005 vs hypo alone. b-c, Plasma glucose (b) and glucagon (c) levels relative to baseline (0 min) during ITTs on Day 1 in control (black), hypo (red), and hypo + Gcg-amide (blue) groups (5 mice/group). Right panels summarise the AUCs of each group. *p < 0.05, **p < 0.01, ***p < 0.001 vs. control. #p < 0.05, ##p < 0.01 vs. hypo alone. d, Schematic of the protocol for in vitro islet function assessment following in vivo conditioning. Wildtype mice were administered with saline (‘control’), insulin (‘hypo’) or the combination of insulin and Gcg-amide (1 mg/kg; ‘hypo+Gcg-amide’) on Day 0. On Day 1, 24 h later, islets were isolated and hormone secretion was tested. e, Plasma glucose levels on Day 0 during in vivo conditioning period in mice that underwent indicated treatments (2 mice/group). f, Glucagon secretion measured at 1 mM glucose in the presence of 100 nM CYN154806 in islets isolated from mice that were subjected to in vivo treatments as indicated 24 h ago (control, n = 10 experiments; hypoglycaemia alone, n = 8 experiments; hypoglycaemia with Gcg-amide, n = 11 experiments; 2 mice/condition). g-i, Plasma glucagon (g), glucose (h), and insulin (i) levels after administration of J60 (0.1 mg/kg, 0 min; arrow) on Day 0 in Gcg-hM3Dq− (black, n = 12 mice) and Gcg-hM3Dq+ (red, n = 9 mice) mice. *p < 0.05, **p < 0.01, ****p = 9.6×10−5 vs. Gcg-hM3Dq−. j, As in (d), but illustrating the protocol used with mice subjected to chemically-induced hyperglucagonemia conditioning. Gcg-hM3Dq− and Gcg-hM3Dq+ mice were administered with J60 or the combination of J60 and Gcg-amide (1 mg/kg; ‘Gcg-amide’) on Day 0. On Day 1, 24 h later, islets were isolated and hormone secretion was tested. k, Plasma glucose levels on Day 0 in in vivo conditioning period in Gcg-hM3Dq− and Gcg-hM3Dq+ mice that underwent indicated treatments (2 mice/group). l, Glucagon secretion measured at 1 mM glucose in the presence of 100 nM CYN154806 in islets isolated from Gcg-hM3Dq− and Gcg-hM3Dq+ mice 24 h after previous in vivo treatments as indicated (Gcg-hM3Dq−, n = 10 experiments; Gcg-hM3Dq+ with J60, n = 9 experiments; Gcg-hM3Dq+ with J60 and Gcg-amide, n = 7 experiments, 2 mice/condition). Symbols and error bars and rectangles and error bars behind data points represent mean values ± S.E.M. Two-sided unpaired t-test was used in (a-c, f-i, l). (d, j) were created with BioRender.com.
