Cardiovascular effects of alloxan diabetes in normotensive and spontaneously hypertensive rats

The diabetogenic effects of alloxan (50 mg/kg i.v.) were recorded for 6 weeks in normotensive (WKY) and spontaneously hypertensive (SHR) rats. While systolic blood pressure increased in diabetic WKY, SHR exhibited a reduction in systolic blood pressure over the 6-week period. Heart rate of treated SHR, but not WKY, was reduced significantly during the course of diabetes. 6 weeks postalloxan, the pressor responses to spinal cord stimulation and various vasoactive agents were significantly reduced in both diabetic groups as compared to their age-matched controls. However, in vitro preparations taken from diabetic and control WKY rats showed similar responsiveness to vasoactive agents. The data suggest that circulatory factors contribute to the decreased in vivo responsiveness.