<i>Id2−/−</i> male mice display enhanced glucose tolerance and insulin sensitivity.

<p>A) Glucose tolerance test (GTT) of young male WT and <i>Id2−/−</i> mice (RM-ANOVA: time (T), P<0.001; Genotype (G), P<0.05; interaction (I), n.s). B) GTT of old male WT and <i>Id2−/−</i> mice (T, P<0.001; G, P<0.05; I, P = 0.001). C) Insulin tolerance test (ITT) of young male WT and <i>Id2−/−</i> mice (T, P<0.001; G, P<0.05; I, n.s.). D) ITT of old male WT and <i>Id2−/−</i> mice (T, P<0.001; G, P<0.01; I, P<0.001). E) Glucose-stimulated insulin release in young male WT and <i>Id2−/−</i> mice (T, P<0.01; G, P<0.01; I, n.s.). F) Glucose-stimulated insulin release in old male WT and <i>Id2−/−</i> mice (T, P = 0.103; G, P<0.01; I, n.s.). No effect of aging was observed in the glucose tolerance of either WT or <i>Id2</i>−/− males (RM-ANOVAs, n.s.). Comparison on young and old <i>Id2−/−</i> males reveal an increase in insulin sensitivity (T, P<0.001; A, P<0.001; I, P<0.01) in the older group. This large age effect was not observed in WTs (T, P<0.001; age (A), p = 0.06; I, P<0.05), although there was tendency for a slower recovery to baseline glucose levels at 90 and 120 mins (p<0.05). Values shown represent mean ± SEM. *p<0.05, **p<0.01 and ***p<0.001.