The present study was undertaken to study the effects of chronic treatment with
lisinopril on the cardiovascular complications in
streptozotocin (STZ) diabetic and deoxycorticosteroneacetate (
DOCA) hypertensive rats. Injection of STZ produced severe
glycosuria (> 2%),
hyperglycemia, hypoinsulnaemia, polydypsia,
polyphagia and loss of
body weight. It also produced
hypothyroidism, hypercholesterolaemia, hypertriglyceridaemia,
hypertension,
bradycardia and decreased left ventricular developed pressure (LVDP). Elevation in serum
creatinine level and increased activity of liver
enzymes were also found in STZ treated animals.
DOCA by itself did not produce any change in
blood glucose but reduced serum
insulin levels in non-diabetic animals. However, in the diabetic group,
DOCA reduced
blood sugar levels. Treatment of STZ-diabetic rats with
DOCA did not aggravate cardiac depression or hyperglycaemia. Treatment of rats with
lisinopril (1 mg kg-1, p.o. daily for six weeks), in diabetic and diabetic hypertensive animals prevented STZ induced loss of
body weight and
hypertension,
bradycardia and
hypothyroidism. It also prevented STZ induced
hyperglycemia and hypoinsulinaemia in both diabetic and diabetic hypertensive animals. There was a reduction in
cholesterol,
triglyceride, and
LDL levels; the ratio between total
cholesterol to HDL and
LDL to HDL and an improvement in LVDP at higher filling pressure in diabetic as well as diabetic hypertensive animals. Treatment with
lisinopril also prevented
hypertrophy and elevated levels of serum
creatinine,
SGOT and
SGPT in diabetic animals. In conclusion, the present data suggests that STZ-
DOCA model may not be considered as the ideal model for the study of cardiovascular complications of combined treatment
hypertension and diabetes. However, the present investigation presents a number of beneficial effects of
lisinopril treatment in diabetic with or without hypertensive rats and it may be considered as one of the drugs of choice in treatment of
hypertension when it is associated with
diabetes mellitus.