The influence of sex and age upon response of white rats to hypoxic hypoxia

Periodic 3-hour daily exposition of white rats to hypoxic hypoxia (standard altitude 8250 m) for 10 days have revealed males and females of both very young and extremely old age groups (“young” - 0,5 months old and “old” - 26 months old) to be more sensitive to chronic hypoxic hypoxia than mature middle-aged animals (“mature” - 3 months old). Their increased sensitivity was apparent in body mass dynamic changes, oxygen consumption, peripheral blood hemoglobin concentration, and red blood cells’ count and peroxidase activity. Parallel to these parameters hypophysis-adrenal system functional activity was assessed according to blood eosynophils’ amount, ascorbic acid adrenals’ concentration, hypophysis and adrenals relative masses changes and “resistance index”. Both male and female rats of “young” and “old” age groups demonstrated variability of different parameters however those characteristic of hypophysis-adrenals system functional activity were practically always involved. Granted non-specific universal adaptation reactions like general adaptation syndrome are of special importance during exposure to any chronic influence, the “young” and “old” animals demonstrated insufficient capacity of hypophysis-adrenals system. However “old” female rats were much more resistant to chronic hypoxic impact revealing the lowest level of hypophysis-adrenals system functional activity.

age-dependant and sex-dependant reactivity, chronic hypoxic hypoxia, hypophysis-adrenals system