OSMOTIC AND ELECTROLYTE CONCENTRATION RELATIONSHIPS DURING THE ABSORPTION OF AUTOGENOUS SERUM FROM ILEAL SEGMENTS

Abstract

Measurements were made of the total osmotic activity, the volume, chloride, acid-labile CO2, Na and H ion conc, changes in autogenous serum placed in ileal segments of anesthetized dogs. There is a rapid absorption of water and chloride from such serum. The Na conc, falls less while the CO2 content rises. The total osmotic activity falls. The av. chloride conc, fall is 36 mE/L in 40 min. The av. Na loss is 10 mE/L in the same time. The av. total CO2 increase is 20 mM/L. The av. net loss of inorganic electrolyte is 13 mM/L, which is identical with the measured decline in total osmotic activity. There is a net absorption of Na and chloride from autogenous serum in ileal loops, in spite of the fact that initially there are no conc, gradients present, and also in spite of the fact that with time the conc. in the gut falls much below that in the circulating blood. The developing hypo-tonicity of originally isotonic solns. in ileal segments was predicted from isotopic tracer studies of absolute rates of movement of water and ions between gut and lumen and blood. Reasons are presented for concluding that active processes occurring at or in the intestinal epithelium must be postulated to occur in order to account for absorption of salt and water for autogenous serum in ileal segments.