Hepatic vascular response to norepinephrine

¹ Department of Surgery, Peter Bent Brigham Hospital, Harvard Medical School, Boston, Massachusetts; and Department of Surgical Research, Michael Reese Hospital and Medical Center, Chicago, Illinois

Norepinephrine injected into the femoral vein or inferior vena cava in doses ranging from 1 to 10 µg/kg produced a prompt and definite decrease in hepatic blood flow; this response was, in general, more pronounced with increasing doses. Femoral venous injections also produced a prompt increase in arterial blood pressure followed by a decreased portal venous pressure and portal-hepatic venous pressure gradient. The calculated hepatic venous resistance increased, reaching a maximum at about 60 sec after injection. When the identical doses were injected into the portal vein in the same animals under comparable conditions, the arterial blood pressure and hepatic blood flow responses were delayed in time and attenuated in amount. However, within 10–15 sec of injection the portal venous pressure and portal-hepatic venous pressure gradient increased. The calculated hepatic venous resistance increased more rapidly after intraportal norepinephrine injection.