Changes in the structure of chromatin in hepatocyte nuclei of rats adapted to hypoxia

Abstract

The structure of chromatin in the nuclei of isolated surviving hepatocytes and of isolated hepatocyte nuclei was studied by fluorochroming with Acridine Orange and microfluorometry of the luminescence of chromatin-bound dye at 530 and 590 nm in intact rats and rats adapted to hypoxia in a pressure chamber for 60 days. Hepatocyte nuclei of intact rats were shown to be distributed on the basis of their fluorescence at 530 nm into three classes, with a ratio between intensities of 1∶2∶4, whereas hepatocyte nuclei of rats adapted to hypoxia formed only one class, corresponding to the second class in the control. The ratio between the intensities of luminescence at 590 nm and 530 nm (the coefficient α) forms a normal distribution in intact rats, but in adapted rats it formed a bimodal distribution with a shaft of the maxima toward both sides of the control. During hypoxia repression of some genes and depression of others is considered to take place in the chromatin of liver nuclei.