| Abstract: | The effects of pharmacological doses of secretin were studied in closed-chest, pentobarbital anesthetized dogs. Infusion of secretin 16 clinical units (CU)/kg-h caused a rise in cardiac output (p less than 0.01), peak first derivative of the left ventricular pressure (p less than 0.01), and heart rate (p less than 0.01) and a fall in systemic arteriolar resistance (p less than 0.01) and left ventricular end-diastolic pressure (p less than 0.01). Stroke volume did not change significantly. Myocardial blood flow and oxygen consumption were unchanged. Secretin caused reductions in arterial lactate (p less than 0.01) and glucose (p less than 0.05) concentrations, and arterial concentrations of free fatty acids and insulin were unaltered. There was no change in myocardial uptake of lactate, glucose, or FFA. Secretin 64 CU/kg-h infused in two dogs caused further changes of the hemodynamic variables. Thus, secretin enhances left ventricular function in intact anesthetized dog by combined vasodilating, inotropic, and chronotropic effects, without changing myocardial oxygen or substrate uptake. |
