Eucalyptus Inhibits Postprandial Hyperfructosemia 207 ingestion, peripheral blood (approximately 0.2 mL) was sampled from the tail, without anaesthesia, by using 26-G needles. Blood variables The SFCs in the portal, cardiac, and peripheral blood samples in Studies 1 and 2 were accurately determined using gas chromatography/mass spectrometry (GC/MS), with 13C6-fructose as an internal standard [14]. The serum glucose concentrations in the cardiac and portal samples (n = 31) were measured using the Glucose B test kit (Wako Pure Chemical Industries, Osaka, Japan). Statistical analysis Values are presented as mean ± SD. Statistical analyses were performed using GB-Stat 5.4 (Dynamic Microsystems, Silver Spring, MD). We analyzed the fructose and glucose concentrations in the serum samples derived from portal and cardiac blood prior to and 30 min after sucrose ingestion by using one-way analysis of variance (ANOVA), followed by the Tukey post hoc test. The changes in the peripheral SFCs were compared between the ELE and control groups by using two-way ANOVA for repeated measures and Bonferroni multiple comparison test for post hoc analyses. Results Effect of ELE on changes in the postprandial SFCs in samples derived from portal and cardiac blood (Study 1) As shown in Fig. 1, the fasting SFCs in the samples derived from portal (A) and cardiac blood (B) were 114 ± 77 μmol/L and 19.8 ± 7.0 μmol/L, respectively. In the control group, after oral sucrose administration, the SFC in the samples derived from portal blood increased transiently, Fig. 1. Eucalyptus leaf extract (ELE) suppresses the postprandial elevation of serum fructose concentrations in samples derived from portal (A) and cardiac (B) blood and does not affect the glucose concentrations (C and D) after a sucrose-tolerance test in rats (Study 1). Mean (SD) fructose and glucose concentrations in the portal and cardiac samples in the control (open circles) and ELE (closed circles) groups. Fasting rats (n = 31) were orally administered water (control group) or ELE at a dose of 1 g/kg body weight (ELE group) prior to the ingestion of sucrose (2 g/kg body weight). The fructose and glucose concentrations in the portal and cardiac samples were determined. Vol. 46, No. 3, 2010