Impact of Reduced Deuterium Intake on Thermoregulation.

The role of stable hydrogen isotopes in the thermoregulation and its regulation is poorly studied. We analyzed fluctuations in body temperature and changes in thermoregulation parameters in mice under conditions of reduced deuterium intake. The study was performed on male C57BL/6 mice that consumed water with a low (10 ppm) and normal (146 ppm) deuterium content. In 7 days, fluctuations of body temperature, locomotor activity, and oxygen uptake were assessed. Deuterium depletion in the body reduced the mean value of minute fluctuations of body temperature and the mean spectral density of minute fluctuations in body temperature in the 2-20-min periods. This attested to a stabilizing effect of deuterium depletion on the rhythms of body temperature fluctuations, without significant shifts in the thermogenesis parameters. Thus, drinking water with reduced deuterium content makes them less sensitive to external influences.

Systemic Effects of Testosterone: Hormonal and Behavioral Mechanisms.

We studied the effects of food deprivation, spatial complexity of environment, and cognitive strain on blood level of testosterone in male (C57Bl/6×DBA/2)F1 mice. Hormone concentration decreased after exposure to any factor and this decrease depended on combined impact to the factors. Testosterone concentration was most sensitive to cognitive strain against the background of food deprivation. The total response of testosterone under conditions of enriched environment and activation of social interactions in the form of neurotic and aggressive behavior provoked by food deprivation was not equal to the sum of individual effects of these factors. Testosterone response to combined exposure to external and internal factors reflected systemic effect.