Blood testosterone in rats: correlation of the level of individual anxiety and its impairment after "death threat".

Studies of identical groups of male Wistar rats after preliminary selection to give groups including extreme behavioral types with low and high rankings on the anxiety scale showed that blood testosterone concentrations in intact rats (controls) correlated negatively with anxiety ranking, i.e., minimal hormone concentrations (no greater than 5 nM) corresponded to high levels of anxiety - with a predominance of passive defensive behavioral components on testing. Short-term exposure to a "death threat" situation (sight of a boa attacking and eating two individuals from the group of rats) impaired this correlational relationship in a manner comparable to the sequelae of chronic neuroticization by unavoidable pain stimulation. Impairments were manifest as scatter in measures in low-anxiety animals (3-21 nM). This characteristic, reflecting the multitude of adaptive pathways in the population in threat situations, distinguishes this type of action from neuroticization by unavoidable pain stimulation, which leveled out individual differences and decreased the hormone level.