Tissue nucleic acids

Abstract

Analyses of corresponding organs in embryo and adult sheep show that embryonic tissue usually has a higher nucleic acid and water content. The presence of ribonucleic and desoxyribonucleic acids in both types of tissue was proved by extracting the nucleic acids with 10% NaCl soln., precipitating them as lanthanum salts, and estimating pentose and desoxypentose in the precipitate. That ribonucleic acids were present in the extracts was confirmed by tests with crystalline ribonuclease. The ratio of ribonucleic acid to desoxyribonucleic acid was of the same order in the embryo and adult tissues, or possibly slightly higher in the latter; it varied widely with the organ, being high in pancreas, liver, testis, brain and heart and low in spleen, lung, and thymus. These results support the view that desoxyribonucleic acid is located in the nucleus and ribonucleic acid mainly in the cytoplasm, and that their conc. in rapidly growing embryonic tissue tends to be high. Acid-soluble purine nucleotides are present in lower conc. in embryonic (and tumor) tissues than in corresponding adult tissues. These results are discussed in relation to tissue growth.