Histochemical Study on the Auran Metamorphosis Enzyme Activities in the Retracting Tail Tissues

During metamorphosis striking changes occur in various organs and tissues of amphibia. Over the years many studies have been carried out and several theories were presented to explain the mechanisms of metamorphosis. One of the present authors has studied connective tissue of the skin during metamorphosis (Niizima, 1955) and the behavior of metamorphosing tissues in tissue culture (Niizima, 1956). In our laboratory, electoron microscopic study of amphibian tissues during metamorphosis is also in progress.Most of the investigations which have been reported up to the present were restricted to histological or experimental studies. Although there have recently been many biochemical studies, the authors have been unable to find any reports of histochemical investigations in this field so far.Since histochemistry shows the distribution of substances in tissue but cannot accurately determine their exact quantities, it becomes necessary, for the understanding of the phenomena in metamorphosis, to compare biochemical data with histochemical findings.In the present investigation, attempts were made to determine whether any changes in the localization of activities of some enzymes in the metamorphosing tail tissue could be detected, in order to clarify which enzymes play an important role in the metamorphosis or involution of the tail.The tail was chosen as the first object of our studies since the retraction of the frog tail is one of the most conspicious phenomena among the many changes occuring during metamorphosis. The enzymes investigated were alkaline and acid phosphatases, leucine aminopeptidase, succinate dehydrogenase and cytochrome oxidase.