Elective surgery is usually performed after an overnight fast. Recent data suggests that pre-operative glucose loading instead of fasting is beneficial for postoperative metabolism by reducing insulin resistance. In this experimental study in rats, we examined the effects of pre-stress glucose infusion on the endocrine response to hemorrhage. Twenty-four hour food deprived rats received a 3 h continuous infusion of 30% glucose (0.3 mg/100 g b.wt./h) or the same volume of normal saline prior to standardized 35% blood loss during 60 min. Infusion of glucose resulted in a six fold increase in liver glycogen, and a twofold higher increment of blood glucose during hemorrhage, compared to saline treated rats. Animals given glucose developed a twofold increase in insulin during hemorrhage, which was not present in saline treated rats. Glucagon, catecholamines and corticosterone levels were elevated in a similar fashion in both groups during hemorrhage. These results indicate that the release of insulin in response to stress can be modulated by pre-treatment with glucose.