Effect of solute-coupled volume absorption on oxygen consumption in cat ileum

The effects of solute-coupled volume absorption on blood flow, oxygen consumption, and vascular resistance were analyzed in autoperfused segments of cat ileum. Intestinal absorption was stimulated by placing either Tyrode solution, Tyrode + glucose, or Tyrode + taurocholate into the ileal lumen. Net volume absorption rates (Jv,m) were determined using a volume recovery method. Oxygen consumption (VO2) increased during the absorption of all solutions. The absorption of Tyrode solution plus glucose caused the greatest increase in VO2, whereas Tyrode plus taurocholate resulted in the smallest increase. For Tyrode solution and Tyrode plus glucose absorption, the increased VO2 was due predominantly to an increased blood flow, whereas the increased VO2 with taurocholate resulted from an increased oxygen extraction. A linear relationship between the change in VO2 during transport and Jv,m was aquired for Tyrode solution, and Tyrode + glucose. The results indicate that the oxygen requirements of the absorbing intestine are dependent on both the rate of transport and the solutes being transported.