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