Mineral metabolism hormones regulating

Steroid hormones have a variety of important functions, including regulation of carbohydrate and mineral metabolism and development of secondary sexual characteristics (Table 20.4). Steroids are often used in the treatment of diseases such as arthritis. Some athletes use steroids to promote muscle growth. 

How does calcium work its wonders on blood pressure This gets a bit technical. The mineral reduces the concentration of parathyroid hormone in the blood that hormone regulates calcium metabolism. In turn, that might lower calcium concentrations in the body s cells and slow the calcium from entering the arteries. Calcium in the arteries affects the tone of the vessels, thus potentially leading to higher blood pressure as the arteries stiffen. 

In this chapter, after an overview of bone and mineral metabolism, we discuss the clinical chemistry of calcium, phosphate, and magnesium the hormones regulating these minerals the major disorders of bone and the clinical use of markers of bone formation and degradation. A goal of the chapter is to provide, in one place, a view of these highly interrelated topics. 

PTH and 1,25-dibydroxyvitamin D are the primary hormones regulating bone and mineral metabolism. Calcitonin has pharmacological actions, but a physiological role has not been established in adults. PTHrP is the principal mediator of hmnoral hypercalcemia of malignancy. 

Vitamin D is produced endogenously by exposure of skin to sunlight, and is absorbed from foods containing or supplemented with vitamin D. Vitamin D is metabolized to its biologically active form, 1,25-dihydroxyvitamin D (1,25[OH]2D), a hormone regulating calcium and phosphate metabolism. Deficiency of vitamin D results in impaired formation of bone, because of a mineralizing defect, producing rickets in children and osteomalacia in adults. 

Vasotocin (VT), H-Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Arg-Gly-NH2 (disulfide bond Cys -Cys ), the evolutionary precursor of the neurohypophyseal hormones. VT has been found in the pineal body of mammals and in the cerebrospinal fluid of humans. It is responsible for the regulation of water and mineral metabolism of lower vertebrates. During transition from the cyclostomata to fish, a gene duplication occurred which resulted in the formation of oxytocin and vasopressin. Only the replacement of Ile in VT by Phe led to vasopressin as the mammalian hormone. Precursors of VT (- hydrins) have been isolated from the pars intermedia of Rana esculenta [F. L. Moore, C. A. Lowry, Comp. Biochem. Physiol. C Pharmacol. Toxicol. Endocrinol. 1998, 119, 251]. 

Progesterone, cortisol, cortisone, aldosterone and related compounds have hormone activity in animals (E 3.1). Progesterone regulates the metabolic activity of the gonads. It is synthesized mainly in the corpus luteum and the placenta. Cortisol, cortisone, and aldosterone influence carbohydrate and mineral metabolism. They are formed in the adrenal cortex (corticosteroids), but also in the gonads and the placenta. All compounds mentioned are used in medicine (F 2) and are produced by the pharmaceutical industry, e.g., from steroid saponins (D 6.4.2) or steroid alkaloids (D 6.4.3). 

Hunter, D., De Lange, M., Snieder, H., et al. 2001. Genetic contribution to bone metabolism, calcium excretion, and vitamin D and parathyroid hormone regulation. J Bone Miner Res, 16 371-8. 

The steroid hormone l/ ,25-dihydroxyvitamin D3 (l/ ,25-(OH)2-D3, calcitriol, 158) is the bioactive metabolite of vitamin D3. This B-ring-seco-steroid plays an important role in the regulation of mineral metabolism and finds application in the treatment of osteodystrophy due to renal failure, rickets, osteoporosis, and psoriasis. The bromoolefin 156 was subjected to sequential metallation and transmetallation to give the corresponding... 

As the human body is able to store many minerals, deviations from the daily ration are balanced out over a given period of time. Minerals stored in the body include water, which is distributed throughout the whole body calcium, stored in the form of apatite in the bones (see p. 340) iodine, stored as thyroglobulin in the thyroid and iron, stored in the form of ferritin and hemosiderin in the bone marrow, spleen, and liver (see p. 286). The storage site for many trace elements is the liver. In many cases, the metabolism of minerals is regulated by hormones—for example, the uptake and excretion of H2O, Na, ... 

The normal thyroid gland secretes sufficient amounts of the thyroid hormones—triiodothyronine (T3) and tetraiodothyronine (T4, thyroxine)—to normalize growth and development, body temperature, and energy levels. These hormones contain 59% and 65% (respectively) of iodine as an essential part of the molecule. Calcitonin, the second type of thyroid hormone, is important in the regulation of calcium metabolism and is discussed in Chapter 42 Agents That Affect Bone Mineral Homeostasis. 

Minerals include sodium, potassium, calcium, phosphorus, magnesium, manganese, sulphur, cobalt and chlorine trace minerals include iron, zinc, copper, selenium, iodine, fluorine and chromium. Their roles may be generalised within the areas of providing structure in the formation of bones and teeth, maintenance of normal heart rhythm, muscle contractility, neural conductivity, acid-base balance and the regulation of cellular metabolism through their activ-ity/structural associations with enzymes and hormones. The daily requirements of minerals can be obtained from a well-balanced diet. 

Mineral elements play a key role in the human body and especially in the regulation of cell metabolism. They are either incorporated into the tissues or else are present in body liquids in ionic form. They also participate in metabolic processes such as electrolyte and hormone economy, haematopoiesis, and development of the nervous and skeletal systems [1,2]. 

CALCIUM The most abundant of the body s minerals an important component of bones and teeth important participant in regulation of many metabolic processes. When bound to the regulatory protein calmodulin, calcium helps modulate the activities of many enzymes. Calcium is important for blood clotting, neural and muscular activity, cell motility, hormone actions, and other activities. 

For instance, urea, the product of protein digestion from which the term urine is derived, must be removed. Other waste products of metabolism must be removed. Any toxins produced by bacteria must be removed. Any drug residue or other unusable material must be removed. Any excess hormone must be removed. Glucose, on the other hand, should not be eliminated and proteins should not be secreted. Vitamins need to be saved, as does calcium and a certain amount of sodium and other minerals. However, water must be regulated. Too much water in the blood would be bad because if blood were too dilute, then not enough nutrients would be transported to the cell. If blood had too little water, then the physical process of pumping the blood around would be... 

Iodine is a trace mineral needed by the body in only very small quantities. It is used in the synthesis of a hormone that regulates basal metabolic rate. Its deficiency results in goiter, a condition in which the thyroid gland swells as it tries to capture as many iodine particles as possible. Iodine deficiency during pregnancy can result in severe retardation of the developing baby. Iodine is readily available in iodized salt, seafood, and milk. The addition of iodine to salt has all but eliminated the effects of its deficiency in developed countries. The DRI for iodine is 150 pig/day, provided by about one-half teaspoon of iodized salt. 

---