THE ACTIVITY OF LACTATE DEHYDROGENASE ISOZYMES DURING THYROXINE-INDUCED TADPOLE METAMORPHOSIS

Abstract

A new improved method to quantitate the amount of the isozymes of lactate dehydrogenase (LDH) has been devised. The method is sensitive and very reproducible. This method has been employed for studies on LDH isozymes during thyroxine-induced tadpole metamorphosis. Only one isozyme is present in tadpole liver whereas three isozymes are present in tadpole tail and brain. Thyroxine treatment produced a decrease of the total LDH activity of tadpole liver, tail, and brain; however, the relative amount of the isozyme F3in tail and brain is the only fraction which shows a decrease. The F1and F2fractions show an increase in relative amount. Thalidomide has no influence on the isozyme pattern of LDH in thyroxine-induced metamorphosis of the tadpole.