Effect of octreotide on fluid absorption and secretion by the normal human jejunum and ileum in vivo

Background: We hypothesized that part of the nonspecific antidiarrhoeal effect of octreotide is mediated by a proabsorptive or antisecretory effect on small intestinal active electrolyte transport. Methods: To measure the effect of octreotide on net absorption, the jejunum and ileum of normal human subjects were perfused with a balanced electrolyte solution: to measure the effect of octreotide on normal active chloride secretion, the jejunum was perfused with a bicarbonate-free solution. Results: During perfusion of a balanced electrolyte solution, octreotide increased basal net fluid absorption in the jejunum and ileum by about 40 mL/h per 30 cm. In the jejunum, octreotide markedly inhibited basal and sham feeding-stimulated active chloride secretion and inhibited water secretion by 28 and 51 mL/h per 30 cm, respectively. Conclusions: Octreotide causes an increase in the net epithelial cell absorption rate of a balanced electrolyte solution in the normal jejunum and ileum. In the jejunum, this proabsorptive effect is mediated mainly by the reduction of normal active electrolyte secretion, rather than by stimulation of normal active electrolyte absorption. These results support the hypothesis that part of the antidiarrhoeal action of octreotide is due to its effects on active electrolyte transport mechanisms by normal epithelial cells of the small intestine.