Time course for plasma 11-hydroxycorticosteroid elevation in rats during stress.

The time course of plasma 11-hydroxysteroid elevation was studied in two stress situations: regular unsignalled foot shock which produces an intermediate steroid elevation and irregular signalled foot shock with the possibility of escape, which produces an extreme steroid elevation. The initial time course for steroid elevation followed a similar pattern for both treatment groups with the exception that in the irregular signalled group the plasma steroid elevation was more pronounced and there was an indication of biphasic response. The results are discussed in terms of possible inhibitory feedback pathways.