This is a hot area of research in endocrinology. As we mentioned on 16 Feb., the endocrine system is full of great examples of negative feedback . Long-loop feedback involves at least one other step in the pathway. Glucocorticoids can also inhibit their own action, although this is not exactly negative feedback in terms of secretion. This down-regulation of the gene makes the target cell less sensitive to cort.
Catecholamines act via membrane receptors, so they elicit much faster responses.
That said, the glucocorticoid component of the stress response is extremely important, as seen in several genetic diseases that disrupt the HPA axis. Information about these stressors reaches the CRH-releasing neurons in the hypothalamus via a fast, direct pathway from the brainstem . Information about these stressors reaches the CRH neurons via a slower, more indirect pathway. Inputs to the CRH neurons from the brainstem pathway can override inputs from other parts of the brain. On the other hand, you don t want to activate a massive stress response just because you re a little nervous before a piano recital, so it makes sense that the forebrain pathways are more indirect and require more processing.