Reversal of jejunal water secretion by glucose in rats exposed to coliform enterotoxins

Abstract

Glucose absorption and glucose-facilitated water transport were assessed in rats exposed to semipurified preparations of the heat-labile (LT) and heat-stable (ST) enterotoxins of Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae by in vivo jejunal perfusion of these toxins alone and with varying amounts of glucose. Progressive increases in the glucose concentration of from 12 to 56 mM resulted in incremental rises in water absorption from perfusates containing each of these toxins, with similar delta water values to those for the electrolyte perfusion solution without toxins. Water secretion was reversed to absorption by the addition of 12 mM glucose when secretion was mild, but 24 mM was required to achieve this in the presence of severe secretion; absolute values for water transport did not return to normal in any instance. Glucose absorption from solutions containing 24 and 56 mM glucose was severely reduced by all of the ST toxins and marginally reduced by some of the LT toxins; the effect of LT was not attributable to the toxin itself, however, but to another unidentified factor present in LT, but not ST, preparations from both toxigenic and nontoxigenic strains. These observations indicate that glucose-facilitated water transport remains intact in intestinal tissue exposed to various coliform enterotoxins and that this occurs despite the presence of impaired glucose absorption in some instances. They provide a rational basis for treatment with oral glucose-electrolyte solutions of persons whose diarrhea is caused by toxigenic coliform bacteria.