Cellular constraints to diffusion: The effect of antidiuretic hormone on water flows in isolated mammalian collecting tubules

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Abstract

These experiments were intended to evaluate the effects of antidiuretic hormone (ADH) on dissipative water transport in cortical collecting tubules isolated from rabbit kidney. In the absence of ADH, the osmotic (Pf, cm sec-1) and diffusional (PDW cm sec-1) water permeability coefficients were, respectively, 6±6 and 4.7±1.3 (SD). When ADH was added to the bathing solutions, Pf and PDW rose to, respectively, 186±38 and 14.2±1.6 (SD). In the absence of ADH, the tubular cells were flat and the lateral intercellular spaces were closed when the perfusing and bathing solutions were, respectively, hypotonic and isotonic; in the presence of ADH, the cells swelled and the intercellular spaces dilated. These data suggest that ADH increased the water permeability of the luminal membranes of the tubules.

Authors

James A. Schafer, Thomas E. Andreoli