Figure 1.

Glucose tolerance to oral, but not intravenous, load deteriorates with age in Zucker fatty diabetes mellitus (ZFDM) fa/fa rats. (a,b) Glucose tolerance tests of ZFDM rats. (a) Oral glucose tolerance test (OGTT) and (b) intravenous glucose tolerance test were carried out on ZFDM rats (n = 5–6). Right: blood glucose levels; left: area under the curve (AUC) of the levels. The data are expressed as the mean ± standard error of the mean. Holm’s method was used for evaluation of statistical significance. **P < 0.01. (c) Plasma glucagon‐like peptide 1 (GLP‐1) and (d) glucose‐dependent insulinotropic polypeptide (GIP) levels during OGTT.