Effects Of Isoflurane Anesthesia On Murine Glucose Metabolism

Maintaining optimal blood glucose (Glu) and insulin (Ins) levels is essential for physiological studies in anesthetized mice. This study examined the temporal effects of varying levels of isoflurane (ISO) anesthesia on blood Glu and Ins levels in mice for 90 min. post‐induction. Male C57BL/6 mice were allowed to breath freely ISO at 1 (n=5), 1.5 (n=7), and 2.0% (n=8) in 100% O2 while body temperature was maintained at 37.1±0.4°C. ECG and respiratory flowrate were monitored. A 0.6μl tail vein blood aliquot was extracted at 5 min. intervals for Glu measurements. Ins was measured from 1ml arterial blood at 1 and 2% ISO in 20 mice euthanized at t=0, 20, 40, 60 and 80 min. Mean heart rates (±SD) were 532±39, 488±39, and 449±23 bpm at 1, 1.5, and 2% ISO respectively (p<0.0001). Glu concentrations (mg/dl) ranged between 155±28–196±76 [1% ISO], 162±43–239±38 [1.5% ISO], and 159±52–205±49 [2.0% ISO]. Ins values ranged between 3.5±0.3–4.2±0.6ng/dl [2% ISO], and 3.4±0.5–4.2±0.9ng/dl at 1% ISO. Glu values were significantly higher in the ISO=1.5 and 2% groups compared to the 1% group (p<0.0001). No significant temporal change was noted in Glu values at the 3 ISO doses. Ins concentrations did not differ significantly between groups. The results confirm that ISO levels ≥1.5% produce a mild hyperglycemic effect, prominent at later time periods post‐induction.