Adrenocortical Glucocorticoid

Adrenocortical hormone (Section 27.6) A steroid hormone secreted by the adrenal glands. There are two types of adrenocortical hormones mineralocorticoids and glucocorticoids. 

Corticotropin (ACTH) is an anterior pituitary hormone that stimulates the adrenal cortex to produce and secrete adrenocortical hormones, primarily the glucocorticoids. 

Corticotropin is used for diagnostic testing of adrenocortical function. This drug may also be used for the management of acute exacerbations of multiple sclerosis, nonsuppurative thyroiditis, and hypercalcemia associated with cancer. It is also used as an anti-inflammatory and immunosuppressant drug when conventional glucocorticoid therapy lias not been effective (see Display 50-1). 

This section of the chapter discusses the hormones produced by the adrenal cortex or the adrenocortical hormones, which are the glucocorticoids and mineralocorticoids. These hormones are essential to life and influence many organs and structures of the body. The glucocorticoids and mineralocorticoids are collectively called corticosteroids. 

Fludrocortisone is used for replacement therapy for primary and secondary adrenocortical deficiency. Even though this drug lias both mineralocorticoid and glucocorticoid activity, it is used only for its mineralocorticoid effects. 

Mitotane (o,p-DDD) -adrenocortical cytotoxin -nausea and vomiting -CNS toxicity—lethargy, vertigo, sedation, dizziness -adrenal insufficiency—must use replacement doses of mineralocorticoids and glucocorticoids -diarrhea -fever -wheezing -flushing... 

The well-appreciated adverse effects of glucocorticoids include hyperglycemia, hypertension, osteoporosis, fluid retention and electrolyte disturbances, myopathies, psychosis, and reduced resistance to infection. In addition, glucocorticoid use may cause adrenocortical suppression. Specific regimens for withdrawal of glucocorticoid therapy have been suggested. 

Effect of glucocorticoid administration on adrenocortical cortisol production (A). Release of cortisol depends on stimulation by hypophyseal ACTH, which in turn is controlled by hypothalamic corticotropin-releasing hormone (CRH). In both the hypophysis and hypothalamus there are cortisol receptors through which cortisol can exert a feedback inhibition of ACTH or CRH release. 

The maximal activity of the adrenal cortex is between 2 and 8 am, and it is minimal between 4 pm and midnight. Exogenous corticosteroids suppress adrenocortical activity the least when given at the time of maximal activity (am). Therefore, administer glucocorticoids in the morning prior to 9 am. 

Pharmacology The naturally occurring adrenal cortical steroids have both anti-inflammatory (glucocorticoid) and salt-retaining (mineralocorticoid) properties. These compounds are used as replacement therapy in adrenocortical deficiency states and may be used for their anti-inflammatory effects. 

Pharmacology These agents are synthetic adrenocortical steroids with basic glucocorticoid actions and effects. Glucocorticoids may decrease number and activity of inflammatory cells, enhance effect of beta-adrenergic drugs on cyclic AMP production, inhibit bronchoconstrictor mechanisms, or produce direct smooth muscle relaxation. Inhaler use provides effective local steroid activity with minimal systemic effect. 

Deoxycortone acetate Modified form of natural corticosteroid (deoxycortone). Is a mineralocorticoid, displays no significant glucocorticoid action Used to treat Addison s disease and other adrenocortical deficiency states... 

The observation that mitotane (Lysodren) could produce adrenocortical necrosis in animals led to its use in the palliation of inoperable adrenocortical adenocarcinomas. A reduction in both tumor size and adrenocortical hormone secretion can be achieved in about half of the patients taking the drug. Because normal adrenocortical cells also are affected, endogenous glucocorticoid production should be monitored and replacement therapy administered when appropriate. 

The steroidal nature of adrenocortical hormones was established in 1937, when Reichstein synthesized desoxycorticosterone. Eventually it was clearly established that the adrenal cortex elaborated a number of hormones and that these compounds differed in their amount of inherent metabolic (glucocorticoid) and electrolyte regulating (mineralocorticoid) activity. The actions of these hormones extend to almost every cell in the body. In humans, hydrocortisone (cortisol) is the main carbohydrate-regulating steroid, and aldosterone is the main electrolyte-regulating steroid. 

In the treatment of secondary adrenocortical insufficiency, lower doses of cortisol are generally effective, and fluid and electrolyte disturbances do not have to be considered, since patients with deficient corticotrophin secretion generally do not have abnormal function of the zona glomerulosa. Since cortisol replacement therapy is required for life, adequate assessment of patients is critical to avoid the serious long-term consequences of excessive or insufficient treatment. In many cases, the doses of glucocorticoid used in replacement therapy are probably too high. Patients should ideally be administered three or more doses daily. To limit the risk of osteoporosis, replacement therapy should be carefully assessed on an individual basis and overtreatment avoided. 

Cortisone acetate and hydrocortisone are usually the corticoids of choice for replacement therapy in patients with primary adrenocortical insufficiency (such as Addison s disease), or after adrenalectomy where both glucocorticoid and mineralo-corticoid replacement is needed. In secondary adrenal insufficiency, associated with inadequate corticotrophin (ACTH) secretion, glucocorticoid replacement alone is usually adequate [62]. 

Interestingly, while peripheral neuroendocrine function appears normal in patients with panic disorder, decreased basal cortisol concentrations have been reported in most studies in PTSD patients. This relative hypocortisolism occurs in the context of increased feedback inhibition of the HPA axis (see Yehuda, 2000). However, a dissociation between central and adrenocortical (re)activity has been found in animal models of severe early-life stress as well as in abused children and women, suggesting that adrenal dysfunction may, at least in part, contribute to hypocortisolism in PTSD. In the face of hypocortisolism, it seems surprising that hippocampal atrophy is one of the most prominent findings in patients with PTSD, including adult survivors of childhood abuse with PTSD (see Newport and Nemeroff, 2000). While increased glucocorticoid sensitivity of hippocampal cells may play a role in the development of hippocampal atrophy, another potential mechanism may involve toxic effects of markedly increased cortisol responses to everyday stress in patients with PTSD. 

Meaney, M.J., Diorio, J., Meaney, M.J., Diorio, J., Francis, D., Wid-dowson, J., LaPlante, P., Caldji, C., Sharma, S. Seckl, J.R., and Plotsky, P.M. (1996). Early environmental regulation of forebrain glucocorticoid receptor gene expression implications for adrenocortical responses to stress. Dev Neurosci 18 49-72. 

Clinically, ACTH stimulation of the adrenals is used diagnostically to detect adrenal insufficiency plasma cortisol levels are measured before and 60 minutes following an intravenous injection of cosyntropin. Adrenocortical insufficiency is known as Addison s disease Addison s classic description, in 1855, namely general debility, remarkable feebleness of the heart, irritability of the stomach, and a peculiar change of the colour of the skin , summarizes the clinical features of this disease, which is uniformly fatal if undetected and untreated. Therapeutically, corticotropin therapy has been essentially abandoned in favor of the direct administration of glucocorticoids. However, ACTH is still rarely used in the treatment of the infantile spasm seizure disorder. 

The remaining steroid lipids constitute two main classes of steroid hormones sex hormones and adrenocortical hormones. The sex hormones include androgens (testosterone, androsterone), estrogens (estrone, estradiol), and progestins (progesterone). The adrenocortical hormones include mineralocorticoids (aldosterone) and glucocorticoids (hydrocortisone). 

As discussed in previous chapters, secretion of adrenocortical steroids is controlled by the pituitary release of corticotrophin (ACTH). The adrenal gland has two main parts, adrenal medulla, which is responsible for the release of catecholamines and adrenal cortex which secretes glucocorticoids. 

This compound, a potent steroid with both glucocorticoid and mineralocorticoid activity, is the most widely used mineralocorticoid. Oral doses of 0.1 mg two to seven times weekly have potent salt-retaining activity and are used in the treatment of adrenocortical insufficiency associated with mineralocorticoid deficiency. These dosages are too small to have important anti-inflammatory or antigrowth effects. 

ANTAGONISTS OF ADRENOCORTICAL AGENTS SYNTHESIS INHIBITORS GLUCOCORTICOID ANTAGONISTS... 

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