Regional blood flow during digestion in the conscious dog.

Blood flows to the major organs of the resting conscious dog were measured prior to and 30 and 90 min after feeding using the radioactive microsphere technique. Mean systemic arterial pressure, heart rate, and arterial PO2, PCO2, and pH, as well as blood flow to the brain, heart, adrenals, skeletal muscle, hepatic artery, and gastric antrum were not significantly changed following the meal. Pancreatic and duodenal and jejunal blood flows increased at both 30 and 90 min, whereas ileal blood flow increased only at 90 min after feeding. Flow to the gastric body increased in only half of the fed animals, but it increased in all of the animals treated with histamine. In all cases where there was an increase in total wall flow the increase was confined to the mucosa-submucosal layer. Blood flow to the colon was unchanged except for a decrease in the distal colon at 30 min. Thus, the cardiovascular response to feeding appears to be limited to those organs and tissues actively involved in digestion.