Cardiovascular effects of secretin in intact rats versus rats with streptozotocin-induced diabetes mellitus.

The present study was aimed to determine the cardiovascular effects of secretin in healthy rats and rats with streptozotocin-induced diabetes mellitus. In vivo studies involved measurements of the systolic and diastolic blood pressure, and heart rate of rats given secretin at the following doses: 0.75; 1.5; 3.0 mumol/kg. In vitro, the isolated heart function was studied according to the modification of Langendorff's method. The cardiac contraction amplitude, heart rate and coronary outflow were measured while secretin was given at the following three doses: 110.0; 485.2; 1100.0 nmol/0.1 ml. The results were compared with effects of secretin in diabetic rats. In vivo, secretin slightly increased systolic and diastolic blood pressure. Diabetes abolished hypertensive effect of the peptide, while the highest dose slightly increased heart rate. Secretin given at two higher doses in vitro increased the amplitude, but did not change the heart rate and coronary outflow. In diabetes, the secretin influence on the amplitude was preserved, the drug did not change the heart rate and at two higher doses increased the coronary outflow. In conclusion, the study has shown that diabetic state changes the cardiovascular effects of secretin.