Figure 419

Normal pituitary-adrenal axis. Corticotropin-releasing factor (CRF) acts to stimulate the release of adrenocorticotropic hormone (ACTH) from the anterior pituitary. ACTH then stimulates the adrenal zona fasciculata and zona reticularis to synthesize and release cortisol (see Figs. 4-2 and 4-3). The increased levels of cortisol feed back to suppress additional release of ACTH. As shown in Figure 4-4, ACTH and cortisol have circadian patterns.

Pituitary

Pituitary

(zona fasciculata zona reticularis)

Pituitary

Pituitary

(zona fasciculata zona reticularis)
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