Carbohydrate tolerance with portal and systemic venous drainage of the pancreas.

Carbohydrate tolerance was studied in 8 dogs with pancreatic venous drainage to the hepatic portal vein and 6 dogs with pancreatic venous drainage to the systemic veins. While systemic venous drainage of the pancreas was associated with higher fasting plasma insulin and lower fasting plasma glucose levels, no significant differences in either glucose clearance or insulin response to glucose were detectable. Therefore, in the maintenance of plasma glucose homeostatis, administration of insulin into the portal vein offers no significant advantages over the easier systemic route.