title: DNA synthesis and mitotic activity in adult atrial cardiocytes in culture.
abstract: Trypsin-dissociated adult rat atrial cardiocytes were exposed to [3H]thymidine for sequential 24-hr periods from day 3 to day 13 of culture. Following preparation for ultrastructural autoradiography, 1000 cells (at each daily interval) were examined with an electron microscope. Maximal incorporation occurred on day 5 when 63% of the cells were labeled. Small secondary peaks of incorporation occurred on days 8 and 11 following previous exposure to fresh serum. Mitotic activity never exceeded 0.5% of all cardiocytes examined. DNA synthesis and mitoses occurred only in immature cardiocytes characterized by subsarcolemmal filaments and Z-bands with or without specific granules; more mature cells were never labeled.
mesh_terms: D000818:Animals; D001345:Autoradiography; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis*; D008854:Microscopy, Electron; D008938:Mitosis; D009206:Myocardium / Q000166:cytology* / Q000648:ultrastructure; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D004247:DNA