Characterization of Ins1^-/-:Ins2^+/+ and Ins1^-/-:Ins2^+/- Islets.

Separate groups of male mice (discrete from cohorts A and B) were used for islet analyses. (a) In vivo 4-h fasted insulin is shown from 25 week-old mice prior to collection of islets to assess (b) Ins2 mRNA, corrected against ß-actin and normalized to CD-fed Ins1^-/-:Ins2^+/+ mice, (c) islet insulin content, and (d) insulin secretion by 150 islets perifused with 3 mM glucose (basal), 15 mM glucose (Glu), and 30 mM KCl, with area under the curve (y-axis units of ng/mL•min) depicted for phases I/II of glucose and KCl stimulation, minus basal secretion. (e) in vivo 4-h fasted insulin is shown from 52 week-old mice prior to collection of islets at 70 weeks to assess (f) Ins2 mRNA, corrected against ß-actin and normalized to HFD-fed Ins1^-/-:Ins2^+/+ mice, (g) islet insulin content, and (h) insulin secretion by 150 islets perifused with 3 mM glucose (basal), 15 mM glucose (Glu), and 30 mM KCl, with area under the curve (y-axis units of ng/mL•min) depicted for phases I/II of glucose and KCl stimulation, minus basal secretion. n = 3–7. Data are means ± SEM, with scatter points to indicate individual values. Dark blue and red represent CD- and HFD-fed Ins1^-/-:Ins2^+/+ male mice, respectively; pale blue and orange represent CD- and HFD-fed Ins1^-/-:Ins2^+/- male mice, respectively. p ≤ 0.05 denoted by * for CD vs HFD, # for Ins1^-/-:Ins2^+/+ vs Ins1^-/-:Ins2^+/-. (#) indicates p = 0.056 for Ins1^-/-:Ins2^+/+ vs Ins1^-/-:Ins2^+/-.