Effects of Cholecystokinin and Metoclopramide on Jejunal Movements of Water and Electrolytes and on Transit Time of Luminal Fluid in Man

The effects of cholecystokinin and metoclopramide upon jejunal transit time of luminal fluid, net movements of water and electrolytes and unidirectional fluxes of sodium were studied in 11 normal subjects, each one being his own control. An intestinal perfusion technique with a four‐lumen tube was used. This allowed a simultaneous determination of mean transit time and absorption rate of water and electrolytes through a 35 cm segment of jejunum, (a) Cholecystokinin induced a significant decrease in mean transit time of fluid along the test segment. This effect was primarily due to a striking reduction (40% or more) in the mean diameter of the intestinal lumen, (b) Simultaneously there was a significant increase in net water, sodium and chloride secretion into the lumen, whereas net transport of potassium and bicarbonate was not affected. The lumen‐to‐blood unidirectional flux of sodium was obviously reduced but the opposite flux did not significantly change, (c) Similar changes in water and electrolyte movements were observed in subjects in whom transit time was primarily decreased by metoclopramide. (d) A close correlation was found between changes in transit time and net water and sodium transport into the lumen, in both cholecystokinin and metoclopramide studies. These results suggest that intestinal hypermotility may result, per se, in an increased secretion rate of water and electrolytes across the proximal small bowel. The implication of these findings in clinical conditions associating watery diarrhoea with intestinal hypermotility is discussed.