Diabetes mellitus and hypertension. State of the art lecture.

In rats with streptozotocin-induced diabetes an increase in arterial blood pressure was observed as early as the first week after the drug was injected. Blood pressure reached maximal values around the fourth week and remained stable for a long period of follow-up. The responsiveness of these rats to the three major vasopressor hormones, angiotensin II, norepinephrine, and vasopressin, was decreased in the early phase of diabetes and returned to normal in the late phase. Acute treatment at the third, sixth, and twelfth weeks with blockers of these vasopressor hormones resulted in a significant fall in blood pressure at the third week with captopril and at the twelfth week with propranolol plus phentolamine. No significant fall was observed when a specific vasopressin inhibitor was administered. Good control of the blood pressure was obtained when these rats were treated chronically with captopril or prazosin, and partial control was achieved when they were fed a low salt diet. An attenuation in arterial blood pressure levels was observed in rats with two-kidney, one clip hypertension when diabetes was induced by streptozotocin. Plasma creatine levels in diabetic rats were significantly higher than those in control rats only in the sixth and twelfth weeks. Electron microscopy revealed some minor glomerular lesions only at the twelfth week.