Fig. 7.3 
The neuroendocrine control of steroid secretion from the adrenal cortex. 
Negative feedback in the hypothalamus and pituitary operates through cortisol and, to a minor extent, through corticosterone. Thus, high cortisol levels suppress ACTH output, whereas low cortisol levels stimulate ACTH production by increasing the release of CRH and also by increasing the sensitivity of ACTH to CRH.