Objective The aim of this study was to investigate the effect of insulin on the heme oxygenase-carbon
monoxide(H0-CO)system
in its basal and induced state.Methods (1)Isolated Wistar rat aorta was cultured in the media containing different concentrations of
insulin 40 μu/ml, 80μU/ml, 160μU/ml, 320 μU/ml, 640 μU/ml and add heme 10 μmol/L(basal state) or 40μmol/L (induced state) for 24 hours. The relative
activity of HO was measured with bilirubin (pmol/g/h). (2) The Wistar rat aortic smooth muscle cells were cultured in the solution containing insulin and heme (consistency same as above) for 24 hours too. The relative amounts of carbon monoxide released into the media were measured with the quantifying carbon monoxide hemoglobin (COHb). Results (1) The HO activities in the basal state were increased, by the insulin, 48.2%, 60.8%, 80.7%, 70.5% and 62.2%, respectively (P<0.05 or<0.01). (2) The COHb in the culture solution of VSMCs were increased, by the insulin (concentrations as above), 8.7%, 18.6%, 40.2%, 17.1%, 7.9%, respectively P<0.05 or <0.01). (3) In the induced state HO activity was not effected by insulin. Conclusion This study suggests that insulin can increase aorta HO activity in the basal state but not in the induced state, and the effect of insulin on HO-CO system is related to the state of HO.