The Importance of the Intestinal Countercurrent Exchanger for 85Kr Absorption from the Feline Gut

Publisher Website
Google Scholar
Abstract
Rate of 85Kr absorption from the feline gut was studied at varying intestinal blood flows induced by i.a. [intraarterial] infusions of a vasodilator drug [isoprenaline] or by lowering arterial inflow pressure. Effects on rate of absorption of distending the intestine by increasing intraluminal pressure from 0-1-5-7 cm H2O and of augmenting rate of luminal perfusion of the 85Kr solution were investigated. Distending the small bowel increased rate of 85Kr absorption at all levels of intestinal blood flow except at the very low and very high blood flow rates. Decreasing blood flow by lowering of arterial perfusion pressure decreased rate of absorption from the distended gut, while it had no effect in the collapsed small intestine. Increasing the rate of luminal perfusion enhanced the rate of 85Kr absorption at all blood flow levels except at the lowest ones. Results are discussed with regard to villous hemodynamics, intestinal countercurrent exchange and intraluminal concentration gradients in the lumen. The countercurrent exchanger apparently represents, under physiological conditions, the major limiting factor for absorption of lipophilic solutes such as 85Kr.

This publication has 14 references indexed in Scilit: