IMPORTANCE OF SODIUM AND GLUCOSE FOR THE ESTABLISHMENT OF A VILLOUS TISSUE HYPER-OSMOLALITY BY THE INTESTINAL COUNTERCURRENT MULTIPLIER

The intestinal countercurrent multiplier has earlier been shown to create an increased tissue osmolality in the villi (Jodal et al. 1978). In the present paper the importance of varying the luminal contents on the creation of the villous hyperosmolality was investigated using the cryoscopic technique described by Jodal et al. (1978). The perfusion solutions used contained 0, 25 or 147 mmol Na/1 and were either provided with mannitol or glucose (30 mmol/1). It was demonstrated that sodium was of particular importance for the establishment of the villous hyperosmolality while glucose only contributed significantly at low luminal sodium concentrations. It is therefore proposed that glucose only in the absence of sodium in the luminal perfusate may effectively participate in the generation of the villous tissue hyperosmolality via the countercurrent multiplication mechanism. © 1979 Scandinavian Physiological Society