Question

(LinkS to an external site. All of the above symptoms have been getting worse. Blood pressure is 170/110, respirations 12/min and some ankle edema (non-pitting) was noted. The limbs seem relatively thin and the trunk thickened, especially between the upper shoulder blades. Diagnosis was made of Cushing disease/syndrome. How could you differentiate between the two? Elevated levels of cortisol has two effects of plasma leading to increased volume: 1) up-regulation of receptors for aldosterone and 2) an increased effectiveness of ADH (either by centrally increasing ADH release or peripherally by increasing the cellular responsiveness). 1. What effects would these two changes (increased responsiveness to aldosterone and ADH) have on Nat, Kt and water levels in the plasma? (Endocrine Mod 3: MO2, M03, CO2, CO3, CO4) 2. Where does cortisol secretion occur, and thus is a potential site of an over- secreting tumor? How else could someone develop Cushing syndrome if not by a tumor in that area? (Endocrine Mod 3: M01, MO2, MO3, CO1, CO2, CO3, C04, CO5) 3. Which of the following influences the secretion of ACTH? (Endocrine Mod 3: M01, MO2, CO1, CO2, CO3) a) Cortisol levels in the plasma b) Corticotropin releasing hormone from the hvnothalamus search W E3 nsen # & % 7 4 5 P U R T Y 1 J L k G D M N V B

Answer 1

1Q).

Aldosterone increases the retention of sodium in the renal tubules and promotes the excretion of potassium ions through the same.

Excessive secretion of aldosterone causes increased sodium and water reabsorption, and excretion of potassium (through the urine). Increased reabsorption of sodium and water increases the fluid volume and blood pressure. Loss of potassium causes hypokalemia and weakness. This condition is called, “primary aldosteronism.”

2Q).

The cortisol secretion occurs in the adrenal cortex. So, adrenal gland is the potential site of an over-secreting tumor. The cortisol secretion can also be increased by ectopic-tumor secretion of ACTH (adrenocorticotropic hormone), which include the thymus, thyroid, and pancreas.