Glucocorticoids adrenocortical hormones

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. 

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. 

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. 

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). 

Deficient animals have an impaired ability to respond to metabolic and physical stress as a result of this decreased adrenocortical hormone synthesis, although this may be accompanied by enhanced sensitivity of target tissues to hormone action. Some strains of rat are susceptible to the development of duodenal ulcers in pantothenic acid deficiency. Ulceration can be prevented by adrenalectomy and is exacerbated by administration of glucocorticoid hormones. 

Steroid hormones (Section 21.8) are produced by the adrenal cortex and the gonads (testes in males, ovaries in females). The adrenocortical hormones include glucocorticoids, which affect carbohydrate metabolism, modulate inflammatory reactions, and are involved in reactions to stress. The mineralocorticoids control the level of excretion of water and salt by the kidneys. If the adrenal cortex does not function adequately, one result is Addison s disease, characterized by hypoglycemia, weakness, and increased susceptibility to stress. This disease is eventually fatal unless it is treated by administration of mineralocorticoids and glucocorticoids to make up for what is missing. The opposite condition, hyperfunction of the adrenal cortex, is frequently caused by a tumor of the adrenal cortex or of the... 

Besides the mineralcorticoid effect on the electrolyte metabolism, the adrenocortical hormones also influence the metabolism of glucose by promoting glycogen formation in the liver, especially from protein. This effect is termed the glucocorticoid effect and is manifested especially by the 11/3-hydroxy compounds. Emphasizing the breakdown of protein, this effect is also called the catabolic effect. The mechanism of this hormone action seems to involve the de novo formation of more enzymes of amino acid metabolism, e.g., tyrosine a-ketoglutarate transaminase, tr5rptophan pyrrolase, etc. (cf. Enzyme Induction, Chapt. VII-7). 

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. 

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