Question

why are the symptoms of adrenal and pituitary Cushing's the same, even though the cause of it are different?

Based on the symptoms of Cushing's, explain whether or not its actions are anabolic or

catabolic.?

The dexamethasone suppression test is used to determine if Cushing's is pituitary based.

Explain why cortisol should remain elevated in those with secondary pathology

Answer 1

1 In Cushing syndrome the level of steroid cortisol is high in the body. It can be due to a tumor in the adrenal gland or pituitary gland. Cortisol is produced by adrenal cortex of adrenal gland. The hormone Adrenocorticotropic hormone (ACTH) is produced by anterior pituitary gland and could stimulate production of cortisol by adrenal cortex . So when there is a tumor or some abnormality in pituitary gland it will lead to increased production of ACTH and which will finally lead to increased production of cortisol and Cushing syndrome. In tumor or abnormality of adrenal gland also cortisol production is more and leads to Cushing syndrome. The net result of tumor in both pituitary gland and adrenal gland is increased production of cortisol and Cushing syndrome.

2. In Cushing syndrome the production of cortisol is increased . Cortisol is having catabolic action. In catabolic reactions complex molecules are broken down and energy is released. The major catabolic action of cortisol is that it promotes gluconeogenesis. It mobilise and increase the availability of all stored substrates like fats, proteins and glucose.

3. Dexamethasone suppression test can identify if the Cushings is pituitary based. Anterior pituitary produce ACTH and ACTH stimulate production of cortisol from adrenal cortex. When there is more cortisol there will be feed back inhibition and production of ACTH will be reduced and vice versa also happens that is when cortisol levels are less more ACTH is produced. Dexamethasone is an exogenous cortisol. It could also produce feed back inhibition to the production of ACTH from pituitary gland. In normal individual low dose of dexamethasone could cause feed back inhibition of ACTH production. But in those patients with tumor in pituitary gland a high dose of dexamethasone is required to cause feed back inhibition of ACTH from pituitary gland. Thus dexamethasone suppression test helps to distinguish whether the Cushing syndrome is due to the problem in pituitary gland or not.

4.Cortisol is having antiinflammatory action. It could supress immune responses. So it's very helpful in treating conditions where the immune response and inflammatory response is high like asthma, COPD, Rheumatoid arthritis, osteoarthritis, multiple sclerosis etc. They are the first line drugs used to prevent rejection after organ transplantation. In all these conditions if cortisol levels is more in the body it will be useful.