Hypothyroidism is not a major determinant of the severe neonatal diabetes and lethality in Glis3^−/− mice. (A) Serum total T4 levels of maternal Glis3^+/+ and Glis3^+/− mice at midgestation (N = 5 to 8). (B) Survival rate of Glis3^+/+ and Glis3^−/− mice treated daily with L-T4 (0.4 µg/g body weight) or vehicle. N = 10 to 12 mice for each group.