Volume regulation in red blood cells

Hagfish erythrocytes lack the anion exchanger (band 3 protein) in their membranes. This protein has been suggested to play a key role in the activation of a regulatory volume decrease in teleost and elasmobranch fishes. A total lack of the ability of cellular volume regulation in hagfish erythrocytes supports this notion. The lack of volume regulation is accompanied by an extreme stability of hagfish erythrocytes when exposed to anisotonic media.