[Hemodynamic changes in waking rats with acute streptozotocin diabetes after administration of the combined V2/V1 vasopressin antagonist].

The hemodynamic effect of combined V2/V1 arginine vasopressin (AVP) antagonist in conscious rats with acute 24 hour streptozotocin (STZ)--induced diabetes was studied using the microsphere technique. The rats were made diabetic with a single intravenous injection of STZ (60 mg/kg). One day after STZ administration the hemodynamic parameters in the experimental animals were measured before and 10 minutes after AVP antagonist injection (50 mg/kg, i.v.). The hemodynamic alterations observed post-antagonist included: 1) an increase in the total peripheral resistance (1.84 +/- 0.15 vs. 1.31 +/- 0.12 mm Hg/ml/min per 100 g before antagonist administration, p < 0.05), 2) a decrease in the cardiac index (49.0 +/- 3.1 vs. 68.7 +/- 5.2 ml/min/100 g before antagonist administration, p < 0.05) and stroke volume (0.40 +/- 0.03 vs. 0.57 +/- 0.06 ml before antagonist administration, p < 0.05), 3) a significant (p < 0.05) decrease in the blood flow to the skin, skeletal muscle, stomach, small intestine and kidneys. The mean arterial pressure and heart rate remained unchangeable post-antagonist. These data suggest that AVP is responsible, at least in part, for prominent hemodynamic alterations observed in conscious rats with 24 hour STZ-induced diabetes.