Effects of prednisolone on glucose tolerance and insulin secretion in the dog

Effects of prednisolone on glucose tolerance and insulin secretion were evaluated in healthy dogs. Dogs were given 1 mg of prednisolone/kg of body weight/day (n = 5) or 2 mg of prednisolone/kg/day (n = 6) orally for 3 weeks. Intravenous glucose tolerance tests (600 mg/kg) were administered before and after treatment to evaluate plasma glucose in fasting dogs, glucose fractional clearance rate, serum insulin in fasting dogs, insulin peak response, total insulin secretion, and insulinogenic index. A significant difference (P less than 0.05) in plasma glucose in fasting dogs was observed for the 2 mg/kg dose, although values were still within the reference range. There was no significant effect on glucose fractional clearance rate (glucose tolerance) or insulin secretion. Seemingly, peripheral insulin resistance resulting in hyperinsulinemia or decreased glucose tolerance could not be identified in association with 1 or 2 mg of prednisolone/kg/day for 3 weeks in healthy dogs.