Fluid and Electrolyte Movement Across Intestinal Wall of Bullfrog

1) Isolated sacs of small and large intestine of the bullfrog incubated at room temperature, transfer water and electrolyte from mucosa to serosa. The transfer of chloride results not only in a net movement but also in creation of concentration gradients which are pronounced in the case of both small and large intestine. There is an increase in bicarbonate concentratiion at the mucosal surface of the small intestine and a decrease in bicarbonate concentration at the mucosal surface of the large intestine. 2) Eversion of the intestines resulted in sacs that were significantly permeable to radio-inulin. Associated with this abnormal permeability, there is a greater transfer of water and smaller ionic concentration gradients develop.