Effect of histamine on intestinal fluid secretion in the dog.

Intra-arterial infusion of histamine into the small intestine caused about a onefold increase of blood flow, edema of the intestinal tissues and mesentery, and produced a copious secretion of fluid. The jejunal secretions had an ionic composition similar to that of plasma, whereas ileal secretions contained high concentrations of HCO3 with relative low concentrations of Cl. The secretions contained protein (1.5 +/- .2 g/100 ml, range 0.5-2.4) with a similar electrophoretic pattern of plasma protein. When lissamine green was present in the blood, it also appeared in the secretion to a considerable concentration. It is inferred from these findings that a major mechanism of fluid secretion by the action of histamine involves a filtration process across the mucosal epithelium by the incrreased tissue fluid pressure due to extensive capillary leak.