Figure 3. Insulin tolerance is impaired in aged ad libitum-fed rats. Glucose response (A) was not different at baseline (time 0) across age groups, but both the response to insulin expressed as (B) percent of baseline over time and (C) the area under the curve (AUC) was significantly elevated in aged rats relative to young. However, there were no age differences in β-hydroxybutyrate (BHB) (D) at baseline, (E) over time following insulin injection or (F) in total AUC in ad libitum-fed rats. Data are represented as group mean {plus minus}1 SEM. * = p < 0.05. For all panels: ad libitum n = 6 young, n = 5 aged.