regulation
Last reviewed 01/2018
Control is through:
- the renin-angiotensin system for salt and water homeostasis
- the hypothalamic-pituitary axis:
- hypothalamus:
- co-ordinates neural input and negative feedback stimulus from haematogenous glucocorticoids
- secretes corticotrophin releasing factor - CRF
- anterior pituitary:
- integrates the signal for release from CRF, which may be increased by the action of antidiuretic hormone, with negative feedback from haematogenous glucocorticoids
- secretes adrenocorticotrophin hormone, ACTH
- ACTH acts on cells of the adrenal cortex to cause the release and synthesis of cortisol; negative feedback of ACTH secretion by cortisol is rapid
- ACTH feedsback on the hypothalamus to inhibit CRF release
- very high doses of ACTH are required to stimulate aldosterone release; aldosterone is primarily under renin-angiotensin control
- release of CRH, and hence, ACTH and cortisol, is in hourly pulses with additionally, a large peak in the early morning, but other substantial peaks occur through the day