[Blood testosterone in rats: correlation with individual anxiety and its derangement after the "death threat"]

After preliminary testing on a multiparameter scale, test and experimental groups of Wistar male rats were formed on the principle of identical distribution of individuals with different anxiety levels. A negative Spearman correlation between the testosterone blood concentration and the level of anxiety was observed in intact rats: the minimum hormonal concentrations (lower than 5 nmol/l) were found in rats with high anxiety, whereas the maximum concentrations (up to 16 nmol/l) corresponded to the higher anxiety level (prevalence of passive defense reactions during testing). After a sort-term exposure to life-threatening situation (viewing of a boa's attacking and devouring two victim rats from the test group), the correlation was deranged because of appearance of a scatter in testosterone blood concentration (from 3 to 21 nmol/l) in rats with low anxiety. Neurotization with inescapable pain stimulation also deranged the initial anxiety-testosterone correlation, but, as distinct from the exposure to life-threatening situation, eliminated individual differences in testosterone concentration at its low level. The results suggest the existence of multiple ways of adaptation to life-threatening situations in a rat population.