Sex- and age-specific increase of blood glucose levels in CST cKO mice. (A) Blood glucose levels measured after a 4 h fasting period at 10, 12, 15, and 19 mo of age under a normal diet. All groups were given a tamoxifen treatment at 4 mo (n = 6–9/genotype for male, n = 10–14/genotype for female). (B) Glucose tolerance test (GTT) after 8 h fasting at 15 mo (4 mo TAM +11) under a normal diet (n = 9/genotype for male, n = 13/genotype for female). (C) Insulin tolerance test (ITT) in 15 mo (4 mo TAM +11) old mice after a 4 h fasting period (n = 8/genotype for male, n = 12/genotype for female). (D) Plasma insulin levels with and without 4 h fasting measured by ELISA (n = 6/genotype for male, n = 7–10/genotype for female). (A,D) Multiple t-test. (B,C) Two-way ANOVA. * p < 0.05, ** p < 0.01.