Influence of prostacyclin on regional blood flow distribution in anesthetized dogs.

Prostacyclin (PGI2), a major metabolite of arachidonic acid, is widely distributed throughout the cardiovascular system and may influence vascular smooth muscle tone. To evaluate the effects of PGI2 on regional blood flow distribution in anesthetized dogs, the tracer microsphere reference sample method was used. Intravenous PGI2 infusions (0.5 and 1.0 microgram/kg/min) increased renal, adrenal, splenic, small intestinal, brain and pituitary blood flow, whereas pancreatic, fundic and skeletal muscle perfusion were diminished by PGI2. Hepatic and myocardial blood flow remained unchanged. This study demonstrates striking differences in regional vascular sensitivity to PGI2, which should be kept in mind when evaluating the potential therapeutic usefulness of PGI2 in a variety of clinical situations.