Changes in DNA, RNA and protein and the activities of acid and alkaline deoxyribonucleases in grey and white matter regions of developing and aging rat cerebrum.

The contents of DNA, RNA and protein and the activities of acid and alkaline deoxyribonucleases in white and grey matter regions of cerebrum at different stages of the life span of rat were studied. The region of white matter, as opposed to grey, exhibited continued growth throughout the period studied (from 1 to 750 days of age). By various biochemical parameters such as DNA, RNA and protein content and the ratio of protein to DNA, it could clearly be seen that between the ages of 225 and 750 days there was a second bout of DNA accumulation in the regions examined. The putative DNA degrading enzymes, acid and alkaline deoxyribonucleases, show a positive correlation with the rapid DNA accretion noticed during developmental stages and again during old age between 225 and 750 days. From these results it is presumed that these enzymes, although degradative in nature, must be playing some important role in the synthesis of DNA itself.