Arginine, 2-amino-5-guanidinovaleric acid, is a basic amino acid with a positively charged guanidinium group. L-arginine is viewed a nonessential amino acid in humans for nitrogen balance and for metabolic purposes in that L-arginine can be synthesized in the human body in sufficient amounts without dietary supply of this amino acid except for optimum growth in young children and for select metabolic disorders involving hepatic ureagenesis and for stress states. It can be synthesized in animal tissue at a rate sufficient for maintenance in the adult but not rapidly enough to support growth in the young animal. It is thus an essential amino acid for growth but not for maintenance. It is difficult to obtain therapeutic amounts in chicken and turkey, thus the food supplement of arginine.
Arginine is contained at large amounts in milt, cuttlefish, garlic, and the like, and can be obtained by purification from these natural sources. In addition, L-arginine, L-arginine hydrochloride, L-arginine L-glutamate, and others which are commercially available can be used. L-arginine is a normal constituent of numerous body proteins and is associated with a variety of essential metabolic cell reactions including the initial amidinotransferase reaction with glycine for creatine synthesis. L-arginine also is a unique endogenous substeate for consitutive nitric oxide synthase (c-NOS) for production of the effector free radical, nitric oxide, in the L-arginine-nitric oxide pathway for messenger agent. In the mammalian body, arginine takes part in the formation of urea yielding ornithine. Arginine may be synthesized in the mammalian body from alpha-ketoglutaric acid, glutamic acid or proline.
Arginine is essential to the metabolism of ammonia that is generated from protein breakdown. It is also needed to transport the nitrogen used in muscle metabolism. Nitric oxide (NO), a molecule produced enzymatically from L-arginine by nitric oxide synthase (NOS), is a mediator of both physiological homeostasis and inflammatory cytotoxicity. Nitric oxide is synthesized from the amino acid L-arginine by NO synthase. NO relaxes vascular smooth muscle and inhibits its proliferation. In addition, NO inhibits the interaction of circulating blood elements with the vessel wall. Nitric oxide activity is reduced in hypercholesterolemia and after vascular injury. Nitric oxide (NO) has been recognized as an unusual messenger molecule with many physiologic roles, in the cardiovascular, neurologic and immune systems. It mediates blood vessel relaxation, neurotransmission and pathogen suppression. NO is produced from the guanidino nitrogen of L-arginine by NO Synthase. L-arginine is a substrate of endothelial nitric oxide synthase (eNOS). Administration of L-arginine will increase the production of nitric oxide (NO) by mass action. L-arginine acts to prolong vasodilatation by inducement of the nitric-oxide synthase pathway. The L-arginine also acts to induce vascular neogenesis through action of endothelial growth factor (EGF) and it acts to induce sensory neogenesis through action of nerve growth factor (NGF). L-arginine is shown to improve/decrease liver functions, to lower cholesterol levels and to inhibit the growth of certain tumors in animal system. Arginine participates in many other important reactions such as nitric oxide synthesis and augmatine or creatine formation. It's the body's most potent blood vessel expander and main blood pressure regulator.
Arginine is one of the body building amino acids and influences several hormone functions. Hormones represent one of the most important mechanisms for communication between different organs and tissues in multicellular organisms. Hormones are known to control the metabolic processes both in growing and mature organisms. Hormone replacement therapy has been used in the past to treat patients who have lost the ability to make the hormones or who have reduced hormone levels. Oral administration of L-arginine can increase growth hormone production in normal non-obese subjects, but less so in obese subjects. Growth hormone (GH) has been implicated in a number of metabolic effects. HGH or human growth hormone is produced in the anterior pituitary gland situated just below the hypothalamus which is itself situated just below the cerebral cortex of the brain. HGH influences the growth, regeneration and repair of cells, bones, muscles and organs throughout the body throughout life. Production peaks at adolescence when accelerated growth is occurring and if growing children are deficient in human growth hormone, they remain as pituitary dwarfs. If they have too much they exhibit gigantism (acromegaly). Daily growth hormone secretion diminishes with age with roughly half the levels at age forty that we had when we were twenty, and about one-third of those youthful levels at age sixty. Low HGH levels are associated with the aging process and early onset of disease. Arginine along with lysine has been demonstrated to cause HGH release when combined in specific proportions. Lysine boosts the effectiveness of arginine and is also said to affect growth as well as having immune-boosting properties of its own. Ornithine can be synthesized in the body and is now also known to help stimulate hGH release. |
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