Water Absorption From the Intestine via Portal and Lymphatic Pathways

Abstract

The content of either D2O or Na24 has been measured in the intestinal lymph, portal venous blood, and femoral arterial blood of unanesthetized hydrated rats after administration of the isotope into the stomach, duodenum, or peripheral or portal vein. Little, if any, water or sodium ion is delivered to the body by a lymphatic pathway after absorption from the small intestine. At least 99% is carried in portal venous blood. The amount of isotope found in intestinal lymph was proportional to lymph volume whatever the route of administration, and derived mainly from the arterial blood. Even during absorption of water or sodium ion from the small intestine the arterial circulation is the principal source of the water and sodium of the lymph.