Distribution of DNA and RNA in the Brain during the Life Span of the Albino Rat

Abstract

DNA, RNA and total protein were determined by quantitative methods in the anterior and posterior halves of the hemisphere, the cerebellum, the thalamus and the brain stem of male albino rats between 0.5 and 36 months of age. There are marked differences in DNA and RNA content between these 5 regions. RNA and DNA reach their adult levels by the first mo. of life or even earlier, whereas protein content continues to increase up to about 6 mo. This results in a marked decrease of RNA and DNA per unit protein during the growth period. There is only a little quantitative loss of DNA and RNA during the adult and senescent periods. It appears that either no overall loss of cells occurs to any significant extent, or that the histologically observed losses of ganglion cells in old age are compensated in part by an increase in glia cells.