QS Study

Cortisol is a steroid hormone that is thought to be taken up in a target cell by simple diffusion. It is often called the “stress hormone” because of its correlation to the stress reaction, however, it is much more than just a hormone released during stress.

Mechanism of action of Cortisol – It can help control blood sugar levels, control metabolism, help decrease inflammation, and assist with memory formulation. cortisol is lipid soluble, it can easily diffuse through the cell membrane.

  1. Diffusion of cortisol to the interior of cells,
  2. Binding of cortisol with an intracellular receptor,
  3. Transcription,
  4. Translation,
  5. The new protein is formed and cellular response occurs.

(According to an action of aldosterone)

Fig: mechanism of action of Adrenocorticotropic hormone (ACTH)

Regulation of cortisol secretion: Secretion of cortisol is controlled almost entirely by ACTH secreted by the anterior pituitary gland. This hormone, also called corticotropin, also enhances the production of adrenal androgens.

(A) Role of ACTH: ACTH stimulates cortisol secretion.

ACTH secretion is also controlled by a corticotropin-releasing hormone from the hypothalamus.

(B) The response to stress: Stressful condition stimulates the secretion of CRH, ACTH and therefore cortisol.

(C) Feedback control of secretion of cortisol: Cortisol has direct negative feedback effects on –

  • The hypothalamus to the formation of CRH,
  • ACTH formation is inhibited by ACTH.

Both of these feedbacks help to regulate the plasma concentration of cortisol.