What are the 4 main functions of ACTH?
1. ACTH stimulates the adrenal cortex and causes the secretion glucocorticoids.
2. Gluco-corticoid is a very essential hormone for an individual to meet the stressful conditions. When an animal is faced with a stressful situation, impulses from the sense organs pass to the brain and then to the hypothalamus. The hypothalamus intern influences adenohypophysis to secrete more quantity of ACTH.
3. Melanocyte pigmentation is also under the control of ACTH and patients in whom there is insufficiency of adrenal secretion are abnormally pigmented as a result of the loss of negative feedback provided by Cortisol. This condition is known as Addison’s disease.
4. There is a diurnal variation in the secretion of ACTH. As a result of this, the Cortisol levels in the plasma will be at its peak in the morning (about 6 am) and will reach their lowest level around midnight. In an abnormality known as Cushing’s disease there is hypersecretion of Cortisol and the diurnal variation is lost.