Cell volume maintenance and regulation in kidney tissues of various vertebrates.

: Ouabain-sensitive and ouabain-insensitive mechanisms are shown to participate to a different extent in the cell volume maintenance in kidney tissues of various vertebrates. The ouabain-insensitive mechanisms predominate in the lamprey and in fresh-water fishes, whereas in the flounder, representing sea fishes, there is a complete predominance of the ouabain-sensitive mechanism. In the rabbit kidney cortex tissue the two systems play a comparable role. Analogous inter-species differences are displayed when the cells regulate their volume in anisoosmolar media.