QS Study

Physiological effects of Cortisol

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.

90-95% cortisol binds with a globulin, called cortisol binding globulin or corticosteroid binding globulin (CBD) or transcortin. It has a controlling effect on salt and water balance and helps control blood pressure.

Binding of cortisol

Cortisol is one of the steroid hormones and is made in the adrenal glands. Transcortin not only binds with cortisol but also corticosterone. Transcortin bound cortisol function as a circulating reservoir of the hormone that keeps a supply of free cortisol available to the tissue.

Cortisol can also bind to albumin.

The half-life of cortisol in circulation is 60 – 90 min.

Bound steroids are physiologically inactive.

Normal total plasma cortisol is 13.5 μg/dL (375mnol/L).

Fig: Physiological effects of Cortisol

Functions of cortisol

(A) Effect on CHO metabolism:

Stimulation of gluconeogenesis –

  • ↑ enzymes required to convert ammo acid into glucose in the liver,
  • ↑ DNA transcription,
  • ↑ Formation of nRNA,
  • ↑ Mobilization of amino acids from muscle into plasma,
  • ↑ Glycogen storage in liver cells,
  • ↓ Glucose utilization by the cells.

(B) Effect on protein metabolism

  • ↑ Protein catabolism and ↓ protein synthesis in all cells except liver.
  • ↑ Hepatic glycogenesis and gluconeogenesis.

(C) Effect on fat metabolism:

  • Promotes mobilization of FA from adipose tissue.
  • of free fatty acids in plasma. So, increase the utilization of energy.
  • β Oxidation of fatty acid in the cells.

Obesity caused by excess cortisol – abnormal deposition of fat giving buffalo-like torso and rounded “moon face.”

(D) Anti-inflammatory effect:

(i) Prevents the development of inflammation by –

  • Stabilizes the lysosomal membrane,
  • ↓ Permeability of capillaries,
  • ↓ Migration of WBC into the inflammatory area and ↓ phagocytosis of damaged cells.
  • Suppress the immune system,
  • A release of IL-1 from T cell.

(ii) Causes resolution of inflammation.

(E) Suppress manifestation of allergic diseases,

(F) Effect of blood cell and immunities –

  • ↓ Eosinophil and lymphocyte,
  • ↓ Immunity,
  • ↑ Production of RBC and TC of WBC.
  • ↓ Basophil,
  • ↑ Monocyte.

(G) Effects on muscular power: Muscular weakness due to excess cortisol.

(H) Effects on CVS:

Cortisol can overcome hypotension associated with adrenocortical insufficiency. Restoring the blood volume and also overcoming myocardial weakness.

(I) Effect on CNS: Irritability, apprehension, inability to concentrate caused by adrenal insufficiency are reversed by cortisol.

(J) Effects on GTT: Promotes the peptic ulcer by increased gastric acid secretion.

(K) Effects on ACTH secretion: Cortisol suppresses secretion of ACTH.

(L) Effects on bone: Decrease the deposition of calcium.

(M) Permissive action.

(N) Resisting stressing.