EFFECT OF HEAT-STABLE AND HEAT LABILE ESCHERICHIA-COLI ENTEROTOXINS, CHOLERA TOXIN AND THEOPHYLLINE ON UNIDIRECTIONAL SODIUM AND CHLORIDE FLUXES IN PROXIMAL AND DISTAL JEJUNUM OF WEANLING SWINE

  • 1 January 1977
    • journal article
    • research article
    • Vol. 41  (3) , 306-317
Abstract
Acute, isolated loops of proximal and distal jejunum of weanling swine were exposed to heat stable porcine E. coli enterotoxin, heat labile porcine E. coli enterotoxin, cholera toxin or theophylline. Unidirectional Na fluxes in response to heat stable enterotoxin in the proximal jejunum were dependent on the length of time that the intestinal mucosae was exposed to the enterotoxin. Net water, Na and chloride and unidirectional Na and chloride flux measurements in the proximal jejunum in response to each agent uniformly indicated that net secretion of fluid and electrolytes was the result of increased unidirectional Na secretion or blood-to-lumen flux and decreased unidirectional chloride absorption or lumen-to-blood flux. Heat stable enterotoxin, cholera toxin and theophylline, but not heat labile enterotoxin decreased unidirectional chloride secretion a small but significant amount in the proximal jejunum. Na and chloride flux measurements in the distal jejunum demonstrated that all 4 secretory agents could stimulated net secretion of water, Na and chloride in that region. The response to these secretory agents as measured by Na and chloride unidirectional flux rates was not similar to changes observed in the proximal jejunum. In the distal small intestine, heat labile enterotoxin, cholera toxin and theophylline induced similar qualitative changes in unidirectional Na and chloride fluxes, while that induced by heat stable enterotoxin differed.