By Ben NeJame and Zach Gardell Addison’s Disease By Ben NeJame and Zach Gardell

What is Addison’s Disease? -An Endocrine or hormonal disorder that occurs when the adrenal glands do not produce enough of certain hormones Symptoms include bronzing of the skin, worsening fatigue, lose of appetite, severe dehydration, and weight loss Can be fatal if left untreated It includes the underproduction of hormones that the adrenal cortex produces

Gland Affected The Adrenal gland, specifically the adrenal cortex, is the gland affected. Addison’s disease develops when the level of adrenal cortex hormone is low due to hyposecretion (lack of secretion).

Hormones Involved Adrenocorticotropic (ACTH) Glucocorticoids (cortisol) Mineralocorticoids (aldosterone)

How Are the Hormones Affected? When Addison’s disease goes into affect, the Anterior pituitary produces excessive but ineffective amounts of Adrenocorticotropic (ACTH) to the adrenal cortex thus hindering its ability to produce and release hormones (Glucocorticoids and Mineralocorticoids). Since there is no ACTH to stimulate the adrenal cortex to release its hormones, the adrenal cortex can not release hormones to regulate processes in the body.

Negative Feedback Loops Within a normal negative feedback loop involving the adrenal cortex the following would happen: The hypothalamus releases hypothalamic inhibitory or releasing hormones to the anterior pituitary. The anterior pituitary then releases ACTH to the adrenal cortex. The adrenal cortex will then release Glucocorticoids (to raise blood glucose levels or to replenish glucose during or after stressful situations) or Mineralocorticoids (to reabsorb sodium and excrete potassium in order to balance water in the body). When their functions are completed, the target tissues of the hormones will release their own hormones back to the hypothalamus in order to stop the release of hormones to affect the body. This represents a negative feedback loop in which the mechanism fluctuates around homeostasis.

Diagram of Normal Feedback Loop Hormone of target tissue Target tissue

Negative Feedback Loops (Continued) In Addison’s diseases, the feedback loop is disrupted. The anterior pituitary releases excessive yet ineffective amounts of ACTH which is supposed to stimulate the adrenal cortex. The adrenal cortex as a result is affected negatively and does not release Glucocorticoids or Mineralocorticoids. Since Glucocorticoids are not produced, glucose cannot be replenished when stressful situations occur. Since Mineralocorticoids are not produced, there is a lack of sodium and water in the body thus leading to severe dehydration. Also, because ACTH exists in excessive yet ineffective amounts, bronzing of the skin occurs because ACTH is linked to melanin production.

Diagram of Addison’s Disease Excessive and ineffective amounts of Adrenal cortex hormones are not released

Works Cited "Adrenal Insufficiency and Addison's Disease." NIDDK. National Institutes of Health, 2009. Web. 27 Mar 2012. <http://endocrine.niddk.nih.gov/pubs/addison/addison.asp&xgt;. Mader, Sylvia S. Understanding Human Anatomy and Physiology. 5th. New York, NY: McGraw-Hill Companies, Inc., 2005. 444. Print. Adrenal Insufficiency and Addison's Disease. 2009. Diagram. NIDDKWeb. 28 Mar 2012. <http://endocrine.niddk.nih.gov/pubs/addison/addison.asp&xgt Image Collection: Skin Problems. 2005. Photograph. Medicine.netWeb. 28 Mar 2012. <http://www.medicinenet.com/script/main/art.asp?articlekey=109861 >. Vitiligo. 2011. Photograph. Healthfiles.netWeb. 28 Mar 2012. <http://healthfiles.net/disease/tag/addisons-disease/>. More Addison's Disease Information. 2009. Diagram. EmpowHERWeb. 28 Mar 2012. <http://www.empowher.com/condition/addisons-disease>.