The aim of the present study was to determine the effect of resveratrol on dipeptidyl
peptidase 4 (DPP-4) and phosphoenolpyruvate carboxykinase (PEPCK) enzyme
activities in streptozotocin (STZ) induced diabetic rats, trying to find an explanation
for its hypoglycemic effect. Sixty male Wistar Albino rats were included in the present
study and classified into three groups, group I (control,non-diabetic), group II
(diabetic group),group ІІІ (diabetic rats treated with resveratrol, 5 mg/kg body
weight/day) for 30 days. After 30 days, blood was collected for determination of;
serum glucose, insulin and DPP-4 enzyme activity. The liver was excised for
estimation of liver glycogen and PEPCK enzyme activity. Serum glucose, DPP-4
activity, and liver PEPCK activity were significantly increased but serum insulin
and liver glycogen were significantly decreased in STZ treated group, while upon
resveratrol treatment , they were all reversed with no significant difference between
group I and group III ( except for final fasting serum glucose level). Conclusion the
antihyperglycemic effect of resveratrol may be related to its stimulatory effect on
insulin ,its suppressive effect on :either DPP-4, so increases the level of incretins with
subsequent increase in insulin release followed by lowering blood glucose level ,or its
inhibitory effect on PEPCK enzyme activity and subsequent decrease in
gluconeogenesis, or, finally its stimulation of glucose utilization by increasing
glycogen formation.