Characterization of male progeny of Irs2^+/–Pdx1^tg intercross. (a and b) Random-fed blood glucose (a) and serum insulin (b) of Irs2^+/–Pdx1^tg intercross mice at 4–5 weeks, 12–13 weeks, and 12–16 months. Results are mean ± SEM of six mice per genotype. *P < 0.05, Irs2^–/– vs. wild-type; **P < 0.01, Irs2^–/– vs. wild-type; ^#P < 0.05, Irs2^–/–Pdx1^tg vs. Irs2^–/–; ^##P < 0.01, Irs2^–/–Pdx1^tg vs. Irs2^–/–. (c) Insulin tolerance test of 4- to 5-week-old fed mice performed with 0.75 U/kg human regular insulin on fed animals. Results are expressed as mean ± SEM of percent of initial blood glucose value for at least eight animals per genotype. *P < 0.05 and **P < 0.01 vs. wild-type. (d) Glucose tolerance tests of 12- to 13-week-old mice performed with 2 g D-glucose per kg body weight after a 15- to 16-hour fast. Results reported as mean ± SEM for at least eight animals per genotype. *P < 0.05 vs. wild-type; **P < 0.01 vs. wild-type; ^##P < 0.01, Irs2^–/–Pdx1^tg vs. Irs2^–/–.