Insulin: Appropriate Placement in the Portal Vein

Subcutaneous insulin administration in the diabetic patient causes peripheral hyperinsulinemia, which contributes to vascular disease, hyperlipidemia and coagulation abnormalities. In the non diabetic patient, insulin is released from the pancreas into the portal system. The majority of this endogenous insulin is taken up by the liver in the first pass so that portal insulin exceeds peripheral insulin. Avoiding peripheral hyperinsulinemia requires that insulin be given orally or administered intra-portally; the latter we have done in diabetic dogs. We propose portal insulin placement in diabetes as physiologic and appropriate in an effort to avoid peripheral hyperinsulinemia and its sequellae.