Intravenous Glucose Tolerance Test and Glucose Kinetic Parameters in Rabbits

The purpose of this study was to determine the normal range and test variability for intravenous glucose tolerance test (IVGTT) in rabbits. Fifty one clinically healthy New Zealand white rabbits of both sexes (31 female and 20 male), 3.5−4 months of age and weighing 2.8 to 3.7 kg were used. The IVGTT was performed after an overnight fasting period of 12 h by intravenous injection of 40% glucose (0.5 g/kg body weight) as a bolus dose over a period of 60 s. Blood samples were collected prior to (0 min) and at 5, 10, 20, 30, 45, 60, 75 and 90 min after glucose administration. The following kinetic parameters of glucose were calculated: half-life time for blood glucose disappearance (t1⁄2β glucose, min), glucose elimination rate constant (Kеl glucose, min ), area under the blood glucose concentration curve versus time (AUCglucose 0−90 min; mmol/L.min). The test was repeated after an interval of 3 weeks in 15 rabbits and coefficients of variation (CV) were calculated by standard methods. The ranges for blood glucose concentration (mmol/L) at 0, 5, 10, 20, 30, 45, 60, 75 and 90 min after IVGTT were 3.8−8.8, 12.8−26.0, 11.5−21.3, 8.9−18.5, 6.6−15.9, 6.0−12.4, 4.8−10.6, 5.3−8.8 and 4.3−8.5, respectively. Means ± SD (range) for Kel glucose, t1⁄2 β glucose, AUCglucose 0−90 min during IVGTT were 0.013 ± 0.004 min (0.0044−0.021 min), 57.5 ± 16.2 min (20–95 min); 922 ± 117 mmol/L.min (642−1202 mmol/L.min), respectively. Mean values did not differ between the two tests performed 3 weeks apart and the intra-individual coefficients of variation for Kel glucose, t1⁄2β glucose, AUCglucose 0−90 min were 16%, 18%, and 17%, respectively, indicating satisfactory reproducibility for these variables with acceptable variation in individual rabbits. Normal ranges for blood glucose concentration at different time points and glucose kinetic parameters after an intravenous glucose tolerance test established in the present study may contribute to better interpretation of test results and provide reliable criteria for the evaluation of normal and impaired glucose tolerance in rabbits.