The changed activity of the serum kallikrein-kinin system after ligation of the superior mesenteric artery in rats.

: The aim of the experiments was to study the effect of ligation of the superior mesenteric artery on the activity of the kinin-kallikrein system in the plasma and on arterial blood pressure. Ligation of 60 minutes did not change the free kallikrein activity of the plasma, while prekallikrein activity significantly decreased. Blood pressure showed a tendency to increase but not to a significant degree. Five minutes after the release of the ligation (during the period when the functional parameters of the intestinal mucosa returned to normal) free kallikrein activity increased and the arterial blood pressure decreased significantly. A rinse of the intestine with 5 p.c. glucose solution prior to the release of ligation prevents the increase in free kallikrein activity and the fall of blood pressure. The substances absorbed from the bowel lumen and activating the kinin system are probably responsible for the circulation failure following the ligation of the superior mesenteric artery.