Changes in serum proteins associated with metamorphosis in salamanders of the family Ambystomatidae.

-l. The effect of metamorphosis on the serum proteins of three genera and five species of ambystomatid salamanders was examined by electrophoresis. 2. Four of the five species showed a significant increase in the fastest fraction upon metamorphosis. 3. Three of the five species showed a significant metamorphic increase in the second fastest fraction. 4. Four of the five exhibited a significant metamorphic increase in total protein. 5. The results support earlier hypotheses that a metamorphic increase in the fast components of amphibian blood serum serves to maintain blood volume in the desiccating, terrestrial environment of the transformed organism.