To determine the effect of an acute increase in hepatic glycogen on net hepatic glucose uptake (NHGU) and disposition in response to insulin in vivo, studies were performed on two groups of dogs fasted 18h. During the first 4h of the study, somatostatin was infused peripherally, while insulin and glucagon were replaced intraportally in basal amounts. Hyperglycemia was brought about by glucose infusion and either saline (n=7) or fructose (n=7; to stimulate NHGU and glycogen deposition) was infused intraportally. A 2h control period then followed, during which the portal fructose and saline infusions were stopped, allowing NHGU and glycogen deposition in the fructose infused animals to return to rates similar to those that received the saline infusion. This was followed by a 2h experimental period, during which hyperglycemia was continued but the insulin infusion was increased 4-fold in both groups. During the initial 4h glycogen loading period, NHGU averaged 1.18 ± 0.27 and 5.55 ± 0.53 mg/kg/min and glycogen synthesis averaged 0.72 ± 0.24 and 3.98 ± 0.57 mg/kg/min in the saline and fructose groups, respectively (p < 0.05). During the 2h hyperinsulinemic period, NHGU rose from 1.5 ± 0.4 and 0.9 ± 0.2 to 3.1 ± 0.6 and 2.5 ± 0.5 mg/kg/min in the saline and fructose groups, respectively, a change of 1.6 mg/kg/min in both groups despite a significantly greater liver glycogen level in the fructose infused group. Likewise, the metabolic fate of the extracted glucose (glycogen, lactate or carbon dioxide) was not different between groups. These data indicate that an acute physiological increase in the hepatic glycogen content does not alter liver glucose uptake and storage under hyperglycemic/ hyperinsulinemic conditions in the dog.