NUCLEIC ACID CONTENTS OF VARIOUS ORGANS IN RATS DURING POSTNATAL GROWTH

Abstract

The contents of fdeoxyrlbonucleic acid] (DNA) and [ribonucleic acid] (RNA) were determined in various organs in intact rats, male or female, during the postnatal growth. There was no sex difference in normal value of both nucleic acids, but an evident correlation between the content i.nd age; the most organs showed higher concentration of nucleic acids in very early period of the postnatal growth. In general, the DNA level snowed a decrease during earlier periods of growth, maintaining a lower value after about 4 weeks of age. The RNA amount varied depending upon organs but not so marked as DNA level. These changes are correlated with the sexual maturation, and especially conspicuous relationships were observed in reproductive and accessory reproductive organs, i.e., in these organs, the level of DNA was higher than that of RNA in earlier stages, and this relation was reversed in later stages. There was no change in amount of both nucleic acids in such organs as the thymus and ovary.