Reaction of human heterochromatin and euchromatin to spermine

The frequency of occurrence of cell nuclei with X-chromatin and Y-chromatin, as well as with diffuse and coarse chromatin network was studied, using cultured human fibroblasts 47XXY and 47XYY, after treatment of the cell with spermin. This treatment failed to change the percentage of the nuclei with the X- and Y-bodies, but significantly increased the frequency of occurrence of the nuclei, with coarse chromatin. The heterochromatic chromosomal segments retarded in metaphase condensation after the action of 5-bromdesoxyuridine increased the length and number when spermin was added to 5-bromdesoxyuridine. The data obtained were attributed to the different sensitivity of euchromatin to the condensating action of spermin and to inertness of heterochromatin.