[Sodium reabsorption and the membrane systems of vertebrate kidneys]

Sodium reabsorption is low in coldblooded animals (the lamprey Lampetra fluviatilis, red salmon Oncorhynchus nerka, carp Cyprinus carpio, frog Rana temporaria, tortoise Agryonemis horsfieldi) being much higher in warmblooded ones (chicken, pigeon, rat). High level of Na transport in warmblooded animals is paralleled by high activity of succinate dehydrogenase as compared with the activity of Na,K-ATPase. The content of monoenoic fatty acids in the glycerophosphatides from frog and tortoise kidneys is higher than that from pigeon and rat ones.