6533b82efe1ef96bd1292689

RESEARCH PRODUCT

Molecular Evolution of Lactate Dehydrogenase in the Developing Nervous Tissue*

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Publisher Summary This chapter describes both electrophoretic and catalytic studies on lactate dehydrogenase (LDH) in the developing brain. It has been found that the enzyme exhibits at birth a composition that gradually changes to attain the final pattern observed in the adult. The neurochemical findings on LDH isozymes parallel the rapid growth in the first days after birth. Isozyme E, which is not present in detectable amounts 2 days after birth, represents 15% of the enzyme on the 22nd day. Similarly, the percentage decrease of isozyme B is quite steep at the beginning. Nevertheless, the final pattern is attained only at the end of the 2nd month that is, when the cerebral cortex is fully organized. The maturation of LDH from diencephalon follows a different time curve. Diencephalon exhibits also a different LDH pattern on starch or agar gel as compared to other brain areas and the major difference is the lower level of fraction E and the higher level of fraction B. In this respect, the pattern of LDH from diencephalon may be assimilated to that of the whole brain before complete maturation. That diencephalon attains its final pattern in a shorter time than the whole brain could also be anticipated from the finding at birth of a considerable amount of isozyme E is not detectable in the whole brain at the same stage.