Fluid reabsorption in the isolated duct of the rat cauda epididymidis

A technique is described fro measurement of rate of fluid reabsorption in a segment of the rat cauda epididymidis in vitro. The basal rate was 2-63 +/- 0-22 mul/cm2/30 min and was dependent on temperature and inhibited by 2,4-dinitrophenol, suggesting that fluid reabsorption is an energy-dependent process. About 50% of the fluid reabsorption was dependent on intraluminal sodium ions. This Na+-dependent component was inhibited by addition of amiloride to the intraluminal fluid and ouabain to the peritubular fluid.