title: [Incorporation of tritiated thymidine into DNA of rat liver: a critique of various evaluation methods].
abstract: We have measured the incorporation of 3H-(methyl)-thymidine by cell cultures of rat foetal liver and in vivo by the livers of young rats stimulated by casein, in order to compare three methods for the extraction of DNA. The DNA was extracted by three different techniques: perchloric acid precipitation, trichloroacetic acid precipitation and phenol extraction, and its specific activity was determined. The radioactive labelling was also determined for the lipid, ribonucleic acid and protein fractions for the two first methods, in both of which 70 p. cent of the incorporated tritium is found in the DNA fraction and about 10 p. cent in each of the other fractions. The determination of the specific radioactivity of DNA gives similar results for the three extraction methods. However, since larger yields were obtained by both acid precipitation techniques than by phenol extraction, we believe them to be more suitable for studies on cell cultures.
mesh_terms: D000818:Animals; D002364:Caseins / Q000494:pharmacology; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis* / Q000302:isolation & purification; D005069:Evaluation Studies as Topic; D005333:Fetus; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008722:Methods; D051381:Rats; D013936:Thymidine / Q000378:metabolism*; D014316:Tritium
chemical_list: D002364:Caseins; D014316:Tritium; D004247:DNA; D013936:Thymidine
vernacular_title: Incorporation de la thymidine tritiée dans le DNA de foie de rat: critique des différentes méthodes d'évaluation