Stimulation of sodium transport and fluid secretion by ouabain in an insect malpighian tubule.

@article{Maddrell1988StimulationOS,
  title={Stimulation of sodium transport and fluid secretion by ouabain in an insect malpighian tubule.},
  author={S H P Maddrell and Jerry Overton},
  journal={The Journal of experimental biology},
  year={1988},
  volume={137},
  pages={265-76}
}
Ouabain, at all concentrations higher than 2 x 10(-7) mol l-1, stimulates the rate at which the Malpighian tubules of the insect, Rhodnius, transport sodium ions and fluid into the lumen. An effect on paracellular movement of sodium ions is unlikely because ouabain makes the electrical potential of the lumen more positive, which would slow diffusion of sodium into the lumen. Radioactive ouabain binds to the haemolymph-facing sides of the tubule cells but not to the luminal face. This binding is… CONTINUE READING