In vitro metabolic effects of gliclazide and glibenclamide in the rat

The actions of gliclazide and glibenclamide on glucose uptake and glycogen deposition by rat hemidiaphragm and glucose utilization by rat epididymal adipose tissue have been examined in vitro. Neither drug exerted an insulin-like action on muscle or adipose tissue with respect to glucose uptake, glycogen deposition or glucose utilization. Neither gliclazide nor glibenclamide augmented the stimulating action of insulin on glucose uptake or glycogen deposition in the rat hemidiaphragm. In a high concentration (1 microgram ml-1), but not in lower concentrations, glibenclamide enhanced the action of insulin in stimulating glucose utilization by rat epididymal adipose tissue. Gliclazide was without any significant effect. Twenty eight day oral treatment with gliclazide did not increase basal or insulin-stimulated glucose uptake or glycogen deposition in rat hemidiaphragm muscle or glucose utilization by epididymal adipose tissue. It is concluded that in normal rats sulphonylureas do not exert important insulin-like actions or insulin potentiating effects.