Hormone, adrenal cortex gonad

Steroid hormones are biosynthesized from cholesterol in the adrenal cortex, gonads, and placenta. These steroids are important hormones for many specific physiological processes. 

IV. First Attempts to Localize Steroid Hormones in the Adrenal Cortex, Gonads, and Placenta... 

The adrenal cortex produces steroidal hormones that are associated with carbohydrate, fat, and protein metabolism, electrolyte balance, and gonadal functions (58). One of these, cortisone [53-06-5] ( ) demonstrated a remarkable ability to relieve the symptoms of inflammatory conditions... 

This section of the chapter discusses FSH, LH, GH, and ACTH. FSH and LH are called gonadotropins because they influence the gonads (the organs of reproduction). GH, also called somatotropin, contributes to the growth of the body during childhood, especially the growth of muscles and bones. ACTH is produced by the anterior pituitary and stimulates the adrenal cortex to secrete the corticosteroids. The anterior pituitary hormone, TSH, is discussed in Chapter 51. Prolactin, which is also secreted by the anterior pituitary, stimulates the production of breast milk in the postpartum patient Additional functions of prolactin are not well understood. Prolactin is the only anterior pituitary hormone that is not used medically. 

Steroid hormones are produced by only two tissue types, the adrenal cortex and the gonads. A summary of the steroid hormones is given in Table 4.2. Steroid hormones are synthesized from cholesterol (Figure 4.2). This sterol lipid may itself be synthesized within the steroidogenic cell or it may be delivered to the cell by circulating lipoprotein complexes such as low density lipoprotein (LDL) or high density lipoprotein (HDL). 

Steroid hormones are produced by adrenal cortex and gonads (testes in males and ovaries In females). Hormones released by the adrenal cortex play very Important... 

The male and female gonads, as well as the placenta of pregnant females and, to a lesser extent, the adrenal cortex, produce a range of steroid hormones which regulate the development and maintenance of reproductive and related functions. As such, these steroid sex hormones have found medical application in the treatment of various reproductive dysfunctions. 

In the animal body three important groups of hormones are formed by the metabolism of cholesterol the progestins, the sex hormones, and the adrenal cortical hormones 249 Their synthesis occurs principally in mitochondria of the adrenal cortex and the gonads. Steroid hormone synthesis is regulated by hormones, such as corticotropin (ACTH), from the anterior pituitary250 (see Chapter 30) and is also dependent upon the recently discovered steroidogenic acute regulatory protein, which in some way promotes the movement of stored cholesterol into mitochondrial membranes.251 252 Some major pathways of... 

Male and female hormones are produced primarily in the gonads. Androgens are synthesized in the testes in the male. In the female, the ovaries are the principal sites of estrogen and progestin production. As discussed in Chapter 29, small amounts of sex-related hormones are also produced in the adrenal cortex in both sexes, which accounts for the fact that small amounts of hormones of the opposite sex are seen in females and males that is, low testosterone levels are seen in females, and males produce small quantities of estrogen. However, under normal conditions, the amounts of sex-related hormones produced by the adrenal cortex are usually too small to produce significant physiologic effects. 

Dehydroepiandrosterone (DHEA) is a precursor hormone secreted by the adrenal cortex and to a lesser extent by the central nervous system (Chapter 40 The Gonadal Hormones Inhibitors). It is readily converted to androstenedione, testosterone, and androsterone. In peripheral tissues, aromatase converts DHEA to estradiol. In the plasma, DHEA is converted to DHEA sulfate (DHEAS). 

The degree to which the B-100.E receptors are expressed in various tissues appears to be a function of the requirement of that tissue for cholesterol. Thus, cell membranes from the adrenal cortex and gonads, organs that require cholesterol for the production of steroid hormones, contain many... 

Tissues that produce hormones include the hypothalamus, anterior and posterior pituitary, adrenal cortex and medulla, gonads, thyroid and parathyroid glands, heart, brain, cells of the gastrointestinal tract, and the pancreas. 

Phospholipids and glycosphingolipids are amphipathic lipid constituents of membranes (Chapter 10). They play an essential role in the synthesis of plasma lipoproteins (Chapter 20) and eicosanoids (Chapter 18). They function in transduction of messages from cell surface receptors to second messengers that control cellular processes (Chapter 30) and as surfactants. Cholesterol is mainly of animal origin and is an essential constituent of biomembranes (Chapter 10). In plasma, cholesterol is associated with lipoproteins (Chapter 20). Cholesterol is a precursor of bile acids formed in the liver of steroid hormones secreted by adrenals, gonads, and placenta and 7-dehydrocholesterol of vitamin D formed in the skin. In tissues, cholesterol exists primarily in the unesterified form (e.g., brain and erythrocytes), although appreciable quantities are esterified with fatty acids in liver, skin, adrenal cortex, and plasma lipoproteins. 

Steroid hormones are extracellular messengers elaborated by the gonads and the adrenal cortex, plus the placenta in pregnant females. A general feature of steroid hormones is that they are not stored for release after synthesis. Levels of circulating hormones are controlled primarily by their rates of synthesis. This, in turn, is often controlled by signals from the brain. 

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... 

---