Adrenal steroids mineralocorticoids

Steroid Hormones and Neurosteroids. Steroids (qv) can affect neuroendocrine function, stress responses, and behavioral sexual dimorphism (78,79) (see Steroids). Mineralocorticoid, glucocorticoid, androgen, estrogen, and progesterone receptors are localized in the brain and spinal cord. In addition to genomic actions, the neurosteroid can act more acutely to modulate the actions of other receptors or ion channels (80). Pregnenolone [145-13-17, ( ) dehydroepiandosterone [53-43-0] C H2 02 (319) are excitatory neurosteroids found in rat brain, independent of adrenal... 

Primary aldosteronism usually results from the excessive production of aldosterone by an adrenal adenoma. However, it may also result from abnormal secretion by hyperplastic glands or from a malignant tumor. The clinical findings of hypertension, weakness, and tetany are related to the continued renal loss of potassium, which leads to hypokalemia, alkalosis, and elevation of serum sodium concentrations. This syndrome can also be produced in disorders of adrenal steroid biosynthesis by excessive secretion of deoxycorticosterone, corticosterone, or 18-hydroxycorticosterone—all compounds with inherent mineralocorticoid activity. 

Gould, E., Woolley, C.S., Cameron, H.A., Daniels, D C., McEwen, B.S. (1991). Adrenal steroids regulate postnatal development of the rat dentate gyrus II. Effects of glucocorticoids and mineralocorticoids on cell birth. J Comp Neurol, 313, 486-93. 

This chapter discusses the pharmacology of the steroid hormones that are produced by the adrenal cortex. The two primary types of adrenal steroids are the glucocorticoids and mineralocorticoids. Small amounts of other steroids such as the sex hormones (androgens, estrogens, and progestins) are also produced by the adrenal cortex. These steroids are discussed in Chapter 30. 

FIGURE 29-1 Pathways of adrenal steroid biosynthesis. Cholesterol is the precursor for the three steroid hormone pathways. Note the similarity between the structures of the primary mineralocorticoid (aldosterone), the primary glucocorticoid (cortisol), and the sex hormones (testosterone, estradiol). See text for further discussion. 

The two principal groups of adrenal steroids are the glucocorticoids and mineralocorticoids. These hormones are synthesized from cholesterol within cells of the adrenal cortex. The primary glucocorticoid produced in humans is cortisol (hydrocortisone), and the primary mineralocorticoid is aldosterone. Glucocorticoids exert a number of effects such as regulation of glucose metabolism, attenuation of the inflammatory response, and suppression of the immune system. Mineralocorticoids are involved primarily in the control of fluid and electrolyte balance. 

The adrenal steroids are divided into three major categories glucocorticoids, mineralocorticoids, and sex hormones. 

Mechanisms of action Actions mineralocorticoid, glucocorticoid Individual adrenal steroids Pharmacokinetics Dosage schedules Choice of adrenal steroid Adverse effects of systemic pharmacotherapy Adrenal steroids and pregnancy Precautions during chronic therapy treatment of intercurrent illness Dosage and routes of administration indications for use... 

Mineralocorticoid and adrenal androgen secretion is also circadian and episodic in nature, but the dynamic swings in concentrations are not as pronounced as with cortisol. It is usually recommended, however, that blood samples for adrenal steroids be collected in the 0700 to 1000 hour tune frame for consistency in result interpretation. 

Aldosterone and cortisol are not the only adrenal steroids with mineralocorticoid and glucorticoid activities. Corticosterone (4-pregnen-ll S,21-diol-3,20-dione), a glucocorticoid about one-fifth as active as cortisol, has little mineralocorticoid activity relative to aldosterone 11-deoxycorticosterone (DOC) (4-pregnen-21-ol-... 

Adrenal steroids are produced in the adrenal cortex, and they can be divided into two subsets glucocorticoids and mineralocorticoids. The glucocorticoids (cortisol, corticosterone) promote the formation of glycogen in the liver and the gluconeogenesis from proteins. Both raise blood sugar levels. Mineralocorticoids (aldosterone) control the electrolyte and water balance. 

Oral corticosteroids have many properties which may be beneficial in acute and chronic pain relief. They are principally anti-inflammatory or immunosuppressant agents that are derived from adrenal steroids and have primarily glucocorticoid activity with limited or no mineralocorticoid activity. 

It was known for some time that even after the corticoids had been separated from crude extracts of the adrenal cortex, the remaining material, the so-called "amorphous fraction" still possessed considerable mineralocorticoid activity. Aldosterone (250), one of the last steroids to be isolated from this fraction, proved to be the active principle. This compound proved to be an extremely potent agent for the retention of salt, and thus water, in body fluids. An antagonist would be expected to act as a diuretic in those edematous states caused by excess sodium retention. Although aldosterone has been prepared by both total and partial synthesis, the complexity of the molecule discouraged attempts to prepare antagonists based directly on the parent compound. 

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

The main endogenous mineralocorticoid is aldosterone, which is mainly produced by the outer layer of the adrenal medulla, the zonaglomerulosa. Aldostorone, like other steroids, binds to a specific intracellular (nuclear) receptor, the mineralocorticoid receptor (MR). Its main action is to increase sodium reabsotption by an action on the distal tubules in the kidney, which is accompanied by an increased excretion of potassium and hydrogen ions. 

Mitotane—if well-tolerated, dose may be doubled on day 3 then, from day 5 onwards, may increase dose by 500 mg every 2-3 days until maximum tolerated dose (8-12 grams daily) has been reached glucocorticoid and mineralocorticoid replacement necessary to prevent adrenal insufficiency increased steroid doses may be needed at times of physiologic stress... 

The answer is e. (Katzung, p 672. Hardman, pp 1477—1978.) Fludrocortisone is a synthetic steroid compound that exhibits profound mineralo-corticoid activity and some glucocorticoid activity Electrolyte and water metabolisms are affected by the administration of this compound. Fludrocortisone promotes the reabsorption of Na and the urinary excretion of K and hydrogen ions in the collecting duct of the nephron. The drug is indicated for mineralocorticoid replacement therapy in primary" adrenal insufficiency... 

The steroid hormones known as mineralocorticoids and glucocorticoids are synthesized in the adrenal cortex of mammals [3]. The physiological mineralocorticoid is... 

Adrenal cortex Glucocorticoids Mineralocorticoids Sex hormones Steroids... 

Angiotensin II has two effects first, as a vasoconstrictor acting via receptors on vascular smooth muscle cells, and second, it stimulates the adrenal cortex gland to produce aldosterone (a mineralocorticoid steroid hormone, see Chapter 4). Aldosterone promotes the reabsorption of sodium from the renal tubule into the bloodstream and the resulting increase in osmolality (osmotic potential) of the blood causes water reabsorption in the nephrons. The outcome is an increase in blood volume and, therefore, pressure which inhibits (by negative feedback) further renin secretion from the JGA. 

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