Differences in the effects of secretin and glucagon on the blood circulation of unanesthetized rats

Carbonized microspheres, 15 mu in diameter and labelled with 85Sr or 51Cr were injected into the left ventricle of unanesthetized male rats to investigate the changes induced by secretin and glucagon in the distribution of cardiac output to various organs including splanchnic organs. Secretin (0.5 U/100 g i.v.) significantly increased the cardiac output distribution to the stomach, small intestine and pancreas, while the percentage distribution of the cardiac output to the heart, lungs and kidneys was unchanged. On the other hand, glucagon (10 microgram/100 g i.v.) significantly increased the cardiac output distribution to the heart, lungs and kidneys, while the distribution to the major splanchnic organs remained unchanged with the exception of hepatic arterial perfusion which was significantly increased by glucagon.