Effect of physical exertion on the diurnal rhythm of the nucleo-cytoplasmic ratios and hepatocyte nuclear volumes in some mammals.

Abstract

The diurnal rhythm of the nucleo-cytoplasm ic ratios and nuclear volumes were studied in mice and rats in a state of training or chronic fatigue brought about by swimming. Moderate measured physical exertion leads to an increase in the fluctuations of the diurnal rhythrn of these cytological parameters of hepatocyte metabolism (volume and nucleo-cytoplasmic ratios), whereas maximal physical exertion disturbs the diurnal rhythm of these parameters and thus provides indirect evidence of serious disturbances of metabolism in the hepatocytes of the fatigued animal. According to the results of recent investigations [i, 2, 5] regular changes take place in the nucleocytoplasmic ratios and the mean nuclear volumes of hepatocytes in mice and rats during the 24-h period. Gubin [1] has shown that diurnal changes in the nucleo-cytoplasm ic ratios and mean nuclear volumes, as well as the ratios between the numbers of diploid and polyploid hepatocyte nuclei in different species of vertebrates are closely connected with the level of their metabolism (with the concentrations of RNA, glycogen, total proteins, neutral lipids, etc.). The object of this investigation was to study the character of the nucleo-cytoplasm ic ratios and nuclear volumes for the hepatocytes of mice and rats under different physiological conditions: physical exertion within physiological limits (training) and prolonged, maximal physical exertion leading to chronic fatigue.