Summary
The behaviour in time of labelled nuclear DNA in the hepatocytes of newborn rats was studied using autoradiographic and biochemical techniques in two groups of experiments. In the first group H3-thymidine was injected to the mothers at the 16th day of pregnancy and the amount of labelled DNA was evaluated in the newborns after delivery. In the second group H3-thymidine was injected to the newborns two hours after birth and the labelled DNA was studied at the same time intervals as the first group. The amount of labelled thymidine incorporated into the first group of animals remains constant for the first three days of life, thereafter a reduction in specific activity of DNA is observed concomitant with an increase of the percentage of labelled nuclei and a decrease of the number of grains per nucleus. These results show that mitotic divisions, which are absent during the first three days of life, take place between the third and sixth days of life. The decrease of the specific activity is therefore due to dilution and not to loss of labelled DNA. In the second group of experiments the DNA labelled with H3-thymidine shows a decrease by about 30–40% per day during the first three days of life accompanied by a decrease in the number of grains per nucleus without changes in the percentage of labelled nuclei. These data show that DNA synthesized during the first day after birth is metabolically unstable, unlike that synthesized during foetal life.
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References
Barnes, D. W. H., Esnouf, M. P., Stocken, L. A.: Some experiments in favour of the cellular hypothesis for the spleen curative factor. In: Advances in radiobiology (G. C. de Hevesy, A. G. Forssberg and T. D. Abbatt, eds.), p. 211–213. Edinburgh and London: Oliver & Boyd 1957
Bennett, L. L., Simpson, L., Skipper, H. E.: On the metabolic stability of nucleic acids in mitotically inactive adult tissues labeled during embrionic development. Biochim. biophys. Acta (Amst.) 42, 237–243 (1960)
Bibbiani, C., Tongiani, R., Viola-Magni, M. P.: Changes of DNA content per nucleus in hepatocytes of rat during the first days of postnatal life. Histochemie 35, 189–198 (1973)
Bibbiani, C., Viola-Magni, M. P.: Catecholamine synthesis and excretion in rats exposed intermittently to cold. J. Physiol. (Lond.) 217, 533–545 (1971)
Bresnick, E., Lanclos, K., Sage, J., Schwartz, A., Jawn, D. H., Busch, H., Unuma, T.: Isolation of and ribonucleic acid synthesis in nuclei of rat fetal liver. Exp. Cell Res. 46, 396–411 (1967)
Hecht, L. T., Potter, V. R.: Nucleic acid metabolism in regenerating rat liver. I. The rate of deoxyribonucleic acid synthesis in vivo. Cancer Res. 16, 988–993 (1956)
Kirby, K. S.: A new method for the isolation of deoxyribonucleic acids: evidence on the nature of bonds between deoxyribonucleic acid and protein. Biochem. J. 66, 495–504 (1957)
Le Bouton, A. V., Marchand, R.: Changes in the distribution of thymidine-3H labeled cells in the growing liver acinus of neonatal rats. Develop. Biol. 23, 524–533 (1970)
Malvaldi, G., Viola-Magni, M. P.: DNA turnover in adrenal medullary cells of different strains of rats and its enhancement after intermittent exposure to cold. Cell Tiss. Kinet. 5, 103–113 (1972)
McKellar, M.: The postnatal growth and mitotic activity of the liver of the albino rat. Amer. J. Anat. 85, 263–295 (1949)
Pelc, S. R.: Turnover of DNA and function. Nature (Lond.) 219, 162–163 (1968)
Pelc, S. R.: Metabolic DNA in ciliated protozoa, salivary gland chromosomes, and mammalian cells. Int. Rev. Cytol. 32, 327–355 (1972)
Pelc, S. R., Viola-Magni, M. P.: III. Decrease of labeled DNA in cells of the adrenal medulla after intermittent exposure to cold. J. Cell Biol. 42, 460–468 (1969)
Post, J., Hoffman, J.: Changes in the replication times and patterns of the liver cell during the life of the rat. Exp. Cell Res. 36, 111–123 (1964)
Roels, H.: “Metabolic” DNS: a cytochemical study. Int. Rev. Cytol. 19, 1–34 (1966)
Rogers, A. W.: Techniques of autoradiography. Amsterdam: Elsevier Scient. Publ. 1973
Stöcker, E., Butter, D.: Die DNA-Synthese in Leber und Niere junger Ratten. Autoradiographische Untersuchungen mit 3H-Thymidin. Experientia (Basel) 24, 704–705 (1968)
Viola-Magni, M. P.: Changes in the DNA content of adrenal medulla nuclei of rats intermittently exposed to cold. J. Cell Biol. 25, 415–433 (1965)
Viola-Magni, M. P.: A radioautographic study with H3-thymidine on adrenal medulla nuclei of rats intermittently exposed to cold. J. Cell Biol. 28, 9–19 (1966a)
Viola-Magni, M. P.: An analysis of DNA loss and synthesis in the rat adrenal medulla nuclei upon cold stimulation. J. Cell Biol. 30, 213–225 (1966b)
Viola-Magni, M. P.: Synthesis and turnover of DNA in hepatocytes of neonatal rats. J. Microscopy 96, 191–203 (1972)
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Bibbiani, C., Viola-Magni, M.P. Metabolic DNA in the hepatocyte nuclei in newborn rats. Histochemistry 43, 63–72 (1975). https://doi.org/10.1007/BF00490155
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DOI: https://doi.org/10.1007/BF00490155