Studies on Kallikreins. VI. Effect of pancreatic kallikrein and kinin on the transport of amino acids and glucose across the rat small intestine.

Abstract

The influence of hog pancreatic kallikrein and kinin on the transport of amino acids or glucose across the rat small intestine was further examined by the in vitro everted sac method and by the in situ mesenteric perfusion technique. Absorption of methionine and glucose into the vascular system was significantly enhanced, as was that of valine, by intra-luminal administration of kallikrein. Transport of methionine, valine and glucose was also enhanced by addition of bradykinin to the serosal fluid of the everted intestine, but no enhancement of glutamic acid transport was observed under the same conditions. The stimulation of in vitro valine transport by kallikrein was inhibited by aprotinin. Valine transport was not affected by addition of trypsin, plasmin or kallikrein to the serosal side, whereas it was significantly increased by addition of 0.01 KU of kallikrein together with 10 μg of kininogen to the serosal side. Valine transport was reduced under anaerobic conditions or by removal of the intestinal epithelial layer. Ouabain or 2, 4-dinitrophenol also inhibited the intestinal transport of valine. Under these conditions (except for ouabain treatment), valine transport was not enhanced by addition of bradykinin to the serosal side. In ouabain-treated intestine, however, bradykinin increased valine transport approximately 1.5 times compared with the control, but the transport was not restored to the normal level. Meanwhile, valine absorption was decreased to about 40% of the normal value by in situ infusion of 1.0 mM ouabain into the mesenteric vascular system, and the rate was restored to the normal level by intra-luminal administration of kallikrein.