Human body hormones

More than 200 peptides have been shown to be essential for the proper functioning of the human body. Hormones are among the peptides for which functions have been identified. 

Reports have appeared in the Hterature of the use of human growth hormone in older men. It has been proposed that a reduction in growth hormone in old age is responsible for increased adipose tissue, loss of lean body mass, and thinning of skin. Current studies conducted on older men indicate the hormone reverses these effects. In the parameters studied the patients resembled those of persons 10 —20 years younger (70). 

Candidate protease inhibitor drugs must be relatively specific for the HIV-1 protease. Many other aspartic proteases exist in the human body and are essential to a variety of body functions, including digestion of food and processing of hormones. An ideal drug thus must strongly inhibit the HIV-1 protease, must be delivered effectively to the lymphocytes where the protease must be blocked, and should not adversely affect the activities of the essential human aspartic proteases. 

Another important function of albumin is its ability to bind various ligands. These include free fatty acids (FFA), calcium, certain steroid hormones, bilirubin, and some of the plasma tryptophan. In addition, albumin appears to play an important role in transport of copper in the human body (see below). A vatiety of drugs, including sulfonamides, penicilhn G, dicumarol, and aspirin, are bound to albumin this finding has important pharmacologic implications. 

There are numerous other compounds which can be determined in human body fluids. For some classes of compounds, e.g. nitrogen compounds, hormones, and sugars, a few reference materials are available. 

First described in 1926 by Perrin [16], the theory was greatly expanded by Weber [17], who developed the first instrumentation for the measurement of FP. Dandliker [18] expanded FP into biological systems such as antigen-antibody reactions and hormone-receptor interactions. Jolley [19] developed FP into a commercial system for monitoring of therapeutic drug levels and the detection of drugs of abuse in human body fluids. 

Figure 6.1 Acids and bases exist in the human body and are necessary for its proper function, including the function of the digestion process. When food is swallowed, it is attacked by stomach acids. The stomach acids need to be neutralized before food can continue down the digestive tract. A hormone called secretin monitors the pH balance in the small intestine and sends chemical signals to other parts of the body, thereby regulating pH balance.

Calcitonin is a polypeptide hormone that (along with PTH and the vitamin D derivative, 1,25-dihydroxycholecalciferol) plays a central role in regulating serum ionized calcium (Ca2+) and inorganic phosphate (Pi) levels. The adult human body contains up to 2 kg of calcium, of which 98 per cent is present in the skeleton (i.e. bone). Up to 85 per cent of the 1 kg of phosphorus present in the body is also found in the skeleton (the so-called mineral fraction of bone is largely composed of Ca3(P04)2, which acts as a body reservoir for both calcium and phosphorus). Calcium concentrations in human serum approximate to 0.1 mg ml-1 and are regulated very tightly (serum phosphate levels are more variable). 

A) Aniline is an aromatic amine that is useful for preparing dyes. (B) Adrenaline is a hormone that is produced hy the human body when under stress. (C) Quinine is an effective drug against malarial fever. 

Here are some insights into how l,25(OH)2D works. Like steroid hormones and retinoic acid, l,25(OH)2D binds to and activates a cytosolic receptor present in most cells of the human body. The activated receptor migrates to the cell nucleus, binds to a specific nucleotide sequence in the nuclear DNA, and acts as a transcription factor. Directly or indirectly, the expression of some 200 genes is affected as a result. 

Trace amounts of iodine are required for a healthy body. Iodine is part of the hormone thyroxin produced by the thyroid gland. Thyroid secretions control the physical and mental development of the human body. A goiter, a swelling of the thyroid gland, is caused by the lack of iodine. Adding thyroid medication and iodized salt to the diet helps prevent this disease. Radioactive iodine (1-131), with a half-life of eight days, is used to treat some diseases of the thyroid gland. 

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, ... 

Human growth hormone (hGH, somatotrophin Figure 8.11) is a polypeptide hormone synthesized in the anterior pituitary. It promotes normal body growth and lactation and influences various aspects of cellular metabolism. 

Estradiol, testosterone, and progesterone are the principal sex hormones from the estrogen, androgen, and progestin gronps, respectively. These hormones are synthesized in the human body starting with cholesterol. 

Proteins are the third major class of biomolecules. The word protein comes from the Greek word proteios meaning primary. Protein is the primary material composing cells. Fifty percent of the human body is composed of proteins, and it is estimated that roughly 100,000 different proteins are found in humans. Protein is a major component of structural and connective tissue found in skin, ligaments, bones, muscles, and tendons. Digestive enzymes, insulin, and other hormones are proteins. 

The ability of human body ceiis to use giucose for energy requires the abiiity of the giucose to pass out of the biood and into the ceiis through the membrane surrounding each ceii. This is made possibie by a substance caiied insuiin, which is made by the pancreas. insuiin is a hormone, a substance that is secreted directiy into the biood and that acts oniy on specific target tissues. 

Cholesterol is a soft waxy substance that is a steroidal alcohol or sterol. It is the most abundant steroid in the human body and is a component of every cell. Cholesterol is essential to life and most animals and many plants contain this compound. Cholesterol biosynthesis occurs primarily in the liver, but it may be produced in other organs. A number of other substances are synthesized from cholesterol including vitamin D, steroid hormones (including the sex hormones), and bile salts. Cholesterol resides mainly in cell membranes. 

Nitric oxide is a reactive, paramagnetic gaseous free radical which is formed in the human body and in other organisms by an enzymatic oxidation of L-arginine (Eq. 18-65). Since about 1980, NO has been recognized as a hormone with a broad range of effects... 

Cholesterol serves two important functions in the body. First, it is a minor component of cell membranes, where it helps to keep the membranes fluid. Second, it serves as the body s starting material for the synthesis of all other steroids, including the sex hormones. Although news reports sometimes make cholesterol sound dangerous, there would be no life without it. The human body obtains its cholesterol both by synthesis in the liver and by ingestion of food. Even on a strict no-cholesterol diet, an adult is able to synthesize approximately 800 mg per day. 

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