INTEGRATED CARDIOVASCULAR FUNCTION IN THE CONSCIOUS STREPTOZOTOCIN-DIABETIC DEOXYCORTICOSTERONE-ACETATE-HYPERTENSIVE RATS

Blood pressure, heart rate, and left ventricular function were measure d in conscious diabetic Sprague-Dawley rats subjected to 5 weeks of de oxycorticosterone acetate (DOCA) treatment which was started 1 week fo llowing intravenous injection of streptozotocin (STZ) (60 mg/kg) to in duce diabetes mellitus. It was found that chronic administration of DO CA in nondiabetic animals caused an increase in blood pressure and fun ctional parameters of left ventricle, and a decrease in heart rate and plasma insulin levels. Normotensive diabetic rats exhibited hyperglyc emia, hypoinsulinemia, and a lower body weight as compared with contro l animals but did not show significant abnormalities in cardiovascular function. DOCA-hypertensive STZ-diabetic rats had similar hyperglycem ia, milder hypoinsulinemia, and a significantly lower rate of left ven tricular relaxation and systolic blood pressure compared with the nond iabetic DOCA-hypertensive animals. It is concluded that the addition o f DOCA hypertension to intact 6-week STZ-diabetic Sprague-Dawley rats results in the occurrence of cardiac dysfunction.