Osmoregulation in red blood cells of Bufo viridis.

The effect of hyperosmotic solution of NaCl, urea and mannitol on Bufo viridis red blood cells were studied. The percentage of water content in B. viridis red blood cells decreased significantly in NaCl and mannitol hypertonic solutions compared to urea hypertonic solution. The urea concentration found in red blood cells in a urea hypertonic solution was significantly higher than in red blood cells acclimated to NaCl and mannitol hypertonic solutions. The Na+ concentration was significantly lower in red blood cells immersed in urea hypertonic solution than in red blood cells immersed in hypertonic NaCl and mannitol solutions. However, the K+ concentration increased at a similar rate in three different hypertonic solutions.