Kidney systemic glucocorticoids

Cortisol and similar glucocorticoids affect a variety of other tissues.62 These hormones affect renal function by enhancing sodium and water reabsorption and by impairing the ability of the kidneys to excrete a water load. They alter central nervous system (CNS) func-... 

Several relatively common disorders result in aldosterone secretion abnormalities and aberrations of electrolyte status. In Addison s disease, the adrenal cortex is often destroyed through autoimmune processes. One of the effects is a lack of aldosterone secretion and decreased Na+ retention by the patient. In a typical Addison s disease patient, serum [Na+] and [CL] are 128 and 96 meq/L, respectively (see Table 16.2 for normal values). Potassium levels are elevated, 6 meq/L or higher, because the Na+ reabsorption system of the kidney, which is under aldosterone control, moves K+ into the urine just as it moves Na+ back into plasma. Thus, if more Na+ is excreted, more K+ is reabsorbed. Bicarbonate remains relatively normal. The opposite situation prevails in Cushing s disease, however, in which an overproduction of adrenocorticosteroids, especially cortisol, is present. Glucocorticoids have mild mineralocorticoid activities, but ACTH also increases aldosterone secretion. This may be caused by an oversecretion of ACTH by a tumor or by adrenal hyperplasia or tumors. Serum sodium in Cushing s disease is slightly elevated, [K+] is below normal (hypokalemia), and metabolic alkalosis is present. The patient is usually hypertensive. A more severe electrolyte abnormality is seen in Conn s syndrome or primary aldosteronism, usually caused by an adrenal tumor. Increased blood aldosterone levels result in the urinary loss of K+ and H+, retention of Na+ (hypernatremia), alkalosis, and profound hypertension. 

Agents that inhibit steps in the steroidogenic pathway and thus alter the biosynthesis of adrenocortical steroids are discussed, as are synthetic steroids that inhibit glucocorticoid action. The effects of corticosteroids are numerous and widespread, and include alterations in carbohydrate, protein, and lipid metabolism maintenance of fluid and electrolyte balance and preservation of normal function of the cardiovascular system, the immune system, the kidney, skeletal muscle, the endocrine system, and the nervous system. 

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