HYPO-PLUS COMBINATION PRODUCT CAPSULE

Indications

• Bladder irrigation during urological surgery
• Irrigation for transurethral resection of the prostate gland
• Irrigation for bladder tumors

Dosage

Children: Refer to the BNF for Children for pediatric dosing guidelines.

Adults: Refer to the product literature for specific dosing information.

Mechanism of action

Glycine binds to strychnine-sensitive and strychnine-insensitive glycine receptors in the central nervous system. The strychnine-sensitive receptor is a chloride channel that enhances inhibitory neurotransmission. This action may contribute to glycine's potential antispastic effects. Additionally, glycine potentiates NMDA receptor-mediated neurotransmission, which may have implications in managing certain neurological conditions, such as neuroleptic-resistant negative symptoms in schizophrenia.

Pharmacodynamics

Glycine plays a crucial role in various biological functions, including energy metabolism and immune response. It is involved in hormone synthesis and helps in modulating neurotransmitter release, particularly in inhibitory pathways. Glycine's ability to enhance chloride conductance in neurons contributes to its antispastic properties and its potential to mitigate oxidative stress in immune responses.

Pharmacokinetics

Glycine is absorbed readily in the gastrointestinal tract and is utilized by the body for protein synthesis and other metabolic functions. The distribution of glycine in the body is widespread, as it is present in various tissues. Glycine is metabolized in the liver and other tissues, with excretion primarily occurring via the kidneys. The pharmacokinetics of glycine can be influenced by factors such as age, renal function, and overall health status.

Adverse effects

• Fluid overload
• Electrolyte imbalance
• Nausea
• Vomiting
• Headache
• Hypotension

Precautions

• Monitor for signs of fluid overload during irrigation
• Use caution in patients with pre-existing electrolyte imbalances
• Careful consideration in patients with renal impairment

Pregnancy

Glycine is generally considered safe for use during pregnancy when used as an irrigation solution, but risks should be discussed with a healthcare provider.

Breast-feeding

Glycine is likely safe during breastfeeding, but limited data is available. Consultation with a healthcare professional is advisable.

Storage

Store in a cool, dry place. Protect from light. Do not freeze.

Formulations

• Glycine 1.5% irrigation solution 3 litre Easyflow bags
• Glycine 1.5% irrigation solution 1 litre Flowfusor bottles
• Glycine 1.5% irrigation solution 1 litre Easyflow bags
• Glycine 1.5% irrigation solution 2 litre Flowfusor bottles

Indications

• Nutritional supplementation
• Support in neurological disorders
• Enhancement of cognitive function

Dosage

Children: Refer to established guidelines for specific dosing recommendations.

Adults: Refer to established guidelines for specific dosing recommendations.

Mechanism of action

Glutamic acid primarily functions as an excitatory neurotransmitter by binding to and activating glutamate receptors, which include NMDA (N-methyl-D-aspartate), AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid), and kainate receptors. This binding leads to an influx of calcium ions and sodium ions into neurons, resulting in depolarization and the propagation of excitatory signals across synapses. It is also involved in the synthesis of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter.

Pharmacodynamics

Glutamic acid has a significant role in neurotransmission, influencing synaptic plasticity, which is essential for learning and memory. It is involved in various physiological processes, including neuronal development and the regulation of synaptic strength. Dysregulation of glutamate signaling is implicated in several neurological disorders, including epilepsy, Alzheimer's disease, and schizophrenia.

Pharmacokinetics

Glutamic acid is rapidly absorbed from the gastrointestinal tract. It is found in high concentrations in the brain and is distributed widely in tissues. The metabolism of glutamate occurs primarily in the brain and liver, where it can be converted to other amino acids or used in the Krebs cycle for energy production. Glutamate is predominantly excreted as ammonia and urea. The half-life of glutamate in the body is relatively short due to its rapid utilization and metabolism.

Contra-indications

• Hypersensitivity to glutamic acid or any of its components
• Severe liver disease

Adverse effects

• Headache
• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• Hypersensitivity reactions such as rash or itching

Interactions

• May interact with medications that alter amino acid metabolism
• Potential interactions with drugs affecting neurotransmitter levels

Precautions

• Use with caution in patients with renal impairment
• Monitor patients with a history of seizures or neurological disorders

Pregnancy

Glutamic acid is generally considered safe in pregnancy, but should be used under medical supervision.

Breast-feeding

It is likely safe during breastfeeding, but caution is advised.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Oral tablets
• Powder for oral solution
• Injectable form

Indications

• Support in catabolic states
• Improvement of gastrointestinal health
• Enhancement of immune function
• Treatment of glutamine deficiency
• Support during chemotherapy

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations.

Adults: Refer to the BNF for specific dosing guidelines.

Mechanism of action

Supplemental L-glutamine may exert its effects through multiple mechanisms. It protects the gastrointestinal tract's integrity, particularly the large intestine, by preventing translocation of Gram-negative bacteria. It serves as a primary fuel for enterocytes, colonocytes, and lymphocytes. By supplying additional L-glutamine, it may reverse catabolic states, enhance lymphocyte proliferation, and support the production of interleukin-2 and interferon-gamma. Furthermore, L-glutamine enhances phagocytosis by immune cells, contributing to improved immune responses.

Pharmacodynamics

Glutamine is crucial for protein synthesis and nitrogen metabolism. It acts as a nitrogen donor in the biosynthesis of various compounds, including other amino acids, purines, and pyrimidines. The enzyme glutamine synthetase converts glutamic acid to glutamine, thereby incorporating ammonia into organic compounds. Additionally, L-glutamine improves the redox potential of nicotinamide adenine dinucleotide (NAD), which is essential in various metabolic pathways.

Pharmacokinetics

Glutamine is widely distributed in body tissues, with skeletal muscle being the primary storage site. It is metabolized primarily in the liver and kidneys. The absorption of glutamine occurs in the intestine, and it is utilized rapidly by tissues with high metabolic demands, particularly during periods of stress or illness. Its plasma half-life is relatively short, necessitating regular supplementation in clinical settings.

Adverse effects

• Nausea
• Vomiting
• Abdominal pain
• Constipation
• Diarrhea
• Headache

Precautions

• Use with caution in patients with a history of liver disease
• Monitor renal function in patients receiving high doses

Pregnancy

Safety during pregnancy has not been established. Use only if clearly needed and the benefits outweigh the risks.

Breast-feeding

It is not known whether glutamine is excreted in human milk. Caution should be exercised when administering to breastfeeding women.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Powder for oral solution
• Capsules

Indications

• Methionine deficiency
• Hepatotoxicity prevention
• Cholesterol management

Mechanism of action

The mechanism of the possible anti-hepatotoxic activity of L-methionine is not entirely clear. It is thought that metabolism of high doses of acetaminophen in the liver leads to decreased levels of hepatic glutathione and increased oxidative stress. L-methionine serves as a precursor to L-cysteine, which has antioxidant properties and is a precursor to glutathione. The antioxidant activity of L-methionine and its metabolites likely contribute to its potential anti-hepatotoxic effects. Methionine also exhibits free-radical scavenging activity and chelating ability due to its sulfur content.

Pharmacodynamics

L-Methionine functions as a primary supplier of sulfur, which is essential for preventing hair, skin, and nail disorders. It aids in lowering cholesterol levels by enhancing the liver's production of lecithin, reducing liver fat, and protecting kidney function. Methionine acts as a natural chelating agent for heavy metals and helps regulate ammonia formation, contributing to ammonia-free urine and reduced bladder irritation. Furthermore, it influences hair follicles and promotes hair growth, in addition to its potential protective effects against hepatotoxins like acetaminophen.

Pharmacokinetics

Methionine is absorbed from the gastrointestinal tract and is distributed throughout the body, where it is utilized in protein synthesis and converted into other metabolites, such as S-adenosylmethionine and L-cysteine. The metabolism of methionine involves several pathways, including transsulfuration to cysteine and incorporation into proteins. The renal clearance of methionine is significant, as it is involved in the regulation of nitrogen balance and the formation of ammonia.

Adverse effects

• Nausea
• Vomiting
• Abdominal pain
• Allergic reactions

Precautions

• Use with caution in patients with liver disease
• Monitor for allergic reactions in sensitive individuals

Pregnancy

There is insufficient evidence to determine the safety of methionine during pregnancy. Consult a healthcare provider before use.

Breast-feeding

It is not known whether methionine is excreted in human milk. Caution is advised when administering to breastfeeding women.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Oral tablets
• Powder for oral solution

Indications

• Support for connective tissue health
• Muscle repair
• Joint and tendon function
• Skin health maintenance
• Cardiovascular support

Dosage

Children: Refer to BNF for Children for appropriate dosing guidance.

Adults: Refer to BNF for appropriate dosing guidance.

Mechanism of action

Proline is glycogenic, and in the kidney, it is oxidized to form L-Glutamic acid via L-Proline oxidase. L-Glutamic acid and L-Ornithine can be converted back to L-Proline through L-Glutamic acid-gamma-semialdehyde. This metabolic pathway underscores its role in amino acid metabolism and collagen synthesis.

Pharmacodynamics

L-Proline is a major amino acid in cartilage, playing a significant role in maintaining skin elasticity and facilitating the repair of muscle and connective tissue damage. It is essential for the immune system and contributes to the structural functions of joints and tendons. Furthermore, L-Proline supports heart muscle function, thereby promoting cardiovascular health.

Pharmacokinetics

L-Proline is metabolized primarily in the liver and kidneys. Its absorption occurs in the gastrointestinal tract following dietary intake. Once absorbed, it participates in various metabolic pathways, including proline metabolism and tRNA charging, which are crucial for protein synthesis.

Pregnancy

Safety during pregnancy has not been established. Consult a healthcare provider before use.

Breast-feeding

Safety during breastfeeding has not been established. Consult a healthcare provider before use.

Storage

Store in a cool, dry place away from direct sunlight.

Formulations

• Powder
• Capsules
• Tablets

Indications

• Essential amino acid supplementation
• Support for liver function
• Improvement of protein synthesis
• Support in the formation of collagen and elastin
• Aid in digestive health

Dosage

Children: Refer to BNF for Children for appropriate dosage guidelines.

Adults: Refer to BNF for appropriate dosage guidelines.

Mechanism of action

L-Threonine acts as a precursor to the amino acids glycine and serine. It aids in protein synthesis by binding with transfer RNA (tRNA) in the cytoplasm, facilitating the translation of messenger RNA (mRNA) into specific proteins. Threonine's role in lipotropic function helps control fat build-up in the liver and enhances nutrient absorption.

Pharmacodynamics

L-Threonine is essential for maintaining proper protein balance in the body. It supports the synthesis of critical structural proteins and plays a role in metabolic functions related to liver health. Threonine also aids in the formation of collagen and elastin, which are vital for skin and connective tissue integrity.

Pharmacokinetics

Threonine is absorbed in the intestines and utilized by various tissues throughout the body. As an essential amino acid, it cannot be synthesized by the body and must be obtained from dietary sources. Once absorbed, threonine is incorporated into proteins or converted into other metabolites as needed for various physiological functions.

Pregnancy

Threonine is generally considered safe during pregnancy as it is an essential amino acid required for fetal development.

Breast-feeding

Threonine is also considered safe during breastfeeding, as it is essential for protein synthesis and overall growth in infants.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Indications

• Depression
• Cognitive enhancement
• Stress management
• Hypothyroidism
• Chronic fatigue
• Narcolepsy

Dosage

Children: Refer to the BNF for Children for appropriate paediatric dosing guidelines.

Adults: Refer to the prescribing information for specific dosing recommendations based on clinical indication.

Mechanism of action

Tyrosine is synthesized from phenylalanine and serves as a precursor for the neurotransmitters norepinephrine and dopamine. By elevating levels of these neurotransmitters in the brain, tyrosine is thought to exert antidepressant effects, improving mood and cognitive function.

Pharmacodynamics

As a nonessential amino acid, tyrosine is critical for synthesizing proteins, enzymes, and muscle tissue. It is linked to mood elevation and has potential antidepressant properties. Tyrosine supplementation may enhance memory and mental alertness, while deficiencies can lead to issues such as hypothyroidism and low blood pressure.

Pharmacokinetics

Tyrosine is absorbed in the intestine and transported to tissues where it is utilized in the synthesis of proteins and neurotransmitters. Its bioavailability can be affected by dietary intake of phenylalanine and other amino acids. The metabolism of tyrosine involves various pathways, including its conversion into neurotransmitters and involvement in the synthesis of melanin and thyroid hormones.

Adverse effects

• Nausea
• Headache
• Fatigue
• Gastrointestinal upset
• Heartburn
• Joint pain

Interactions

• MAO inhibitors may enhance the effects and side effects of tyrosine
• Thyroid medications may interact with tyrosine supplementation

Precautions

• Use with caution in individuals with hyperthyroidism
• Caution in patients with a history of melanoma or other skin cancers due to tyrosine's role in melanin production

Pregnancy

Tyrosine supplementation should be avoided during pregnancy unless prescribed by a healthcare provider.

Breast-feeding

Consult a healthcare provider before using tyrosine while breastfeeding.

Storage

Store in a cool, dry place away from direct sunlight.

Formulations

• Capsules
• Tablets
• Powder for oral solution

Mechanism of action

In the CNS, there exist strychnine-sensitive glycine binding sites as well as strychnine-insensitive glycine binding sites. The strychnine-insensitive glycine-binding site is located on the NMDA receptor complex. The strychnine-sensitive glycine receptor complex is comprised of a chloride channel and is a member of the ligand-gated ion channel superfamily. The putative antispastic activity of supplemental glycine could be mediated by glycine's binding to strychnine-sensitive binding sites in the spinal cord. This would result in increased chloride conductance and consequent enhancement of inhibitory neurotransmission. The ability of glycine to potentiate NMDA receptor-mediated neurotransmission raised the possibility of its use in the management of neuroleptic-resistant negative symptoms in schizophrenia. Animal studies indicate that supplemental glycine protects against endotoxin-induced lethality, hypoxia-reperfusion injury after liver transplantation, and D-galactosamine-mediated liver injury. Neutrophils are thought to participate in these pathologic processes via invasion of tissue and releasing such reactive oxygen species as superoxide. In vitro studies have shown that neutrophils contain a glycine-gated chloride channel that can attenuate increases in intracellular calcium and diminsh neutrophil oxidant production. This research is ealy-stage, but suggests that supplementary glycine may turn out to be useful in processes where neutrophil infiltration contributes to toxicity, such as ARDS. HYPERPOLARIZATION OF MOTONEURONS PRODUCED BY IONTOPHORETIC APPLICATION OF GLYCINE IS RELATIVELY TRANSIENT BUT APPROACHES THE EQUILIBRIUM POTENTIAL FOR THE INDIRECTLY ACTIVATED INHIBITORY POSTSYNAPTIC POTENTIAL...TESTS WITH GABA... INDICATE SIMILAR ELECTROPHYSIOLOGICAL EFFECTS & SIMILAR INCR IN CL- CONDUCTANCE. MAJOR EVIDENCE THAT FAVORS GLYCINE AS MEDIATOR OF INTRASPINAL POSTSYNAPTIC INHIBITION IS THE SELECTIVE ANTAGONISM OF ITS EFFECTS BY STRYCHNINE. ... GLYCINE ALSO APPEARS TO BE MOST LIKELY TRANSMITTER FOR INHIBITORY INTERNEURONS IN RETICULAR FORMATION BUT NOT IN CUNEATE NUCLEUS.

Pharmacodynamics

Helps trigger the release of oxygen to the energy requiring cell-making process; Important in the manufacturing of hormones responsible for a strong immune system.

Mechanism of action

Supplemental L-glutamine's possible immunomodulatory role may be accounted for in a number of ways. L-glutamine appears to play a major role in protecting the integrity of the gastrointestinal tract and, in particular, the large intestine. During catabolic states, the integrity of the intestinal mucosa may be compromised with consequent increased intestinal permeability and translocation of Gram-negative bacteria from the large intestine into the body. The demand for L-glutamine by the intestine, as well as by cells such as lymphocytes, appears to be much greater than that supplied by skeletal muscle, the major storage tissue for L-glutamine. L-glutamine is the preferred respiratory fuel for enterocytes, colonocytes and lymphocytes. Therefore, supplying supplemental L-glutamine under these conditions may do a number of things. For one, it may reverse the catabolic state by sparing skeletal muscle L-glutamine. It also may inhibit translocation of Gram-negative bacteria from the large intestine. L-glutamine helps maintain secretory IgA, which functions primarily by preventing the attachment of bacteria to mucosal cells. L-glutamine appears to be required to support the proliferation of mitogen-stimulated lymphocytes, as well as the production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma). It is also required for the maintenance of lymphokine-activated killer cells (LAK). L-glutamine can enhance phagocytosis by neutrophils and monocytes. It can lead to an increased synthesis of glutathione in the intestine, which may also play a role in maintaining the integrity of the intestinal mucosa by ameliorating oxidative stress. The exact mechanism of the possible immunomodulatory action of supplemental L-glutamine, however, remains unclear. It is conceivable that the major effect of L-glutamine occurs at the level of the intestine. Perhaps enteral L-glutamine acts directly on intestine-associated lymphoid tissue and stimulates overall immune function by that mechanism, without passing beyond the splanchnic bed. The exact mechanism of L-glutamine's effect on NAD redox potential is unknown but is thought to involve increased amounts of reduced glutathione made available by glutamine supplementation. This improvement in redox potential reduces the amount of oxidative damage which sickle red blood cells are more susceptible to. The reduction in cellular damage is thought to reduce chronic hemolysis and vaso-occlusive events. L-glutamine has important functions in regulation of gastrointestinal cell growth, function, and regeneration. Under normal conditions, glutamine concentration is maintained in the body by dietary intake and synthesis from endogenous glutamate. Data from clinical studies indicate that the role of and nutritional requirements for glutamine during catabolic illness, trauma, and infection may differ significantly from the role of and nutritional requirements for glutamine in healthy individuals. Glutamine concentrations decrease and tissue glutamine metabolism increases during many catabolic disease states, and thus glutamine is often considered a "conditionally essential" amino acid.

Pharmacodynamics

Like other amino acids, glutamine is biochemically important as a constituent of proteins. Glutamine is also crucial in nitrogen metabolism. Ammonia (formed by nitrogen fixation) is assimilated into organic compounds by converting glutamic acid to glutamine. The enzyme which accomplishes this is called glutamine synthetase. Glutamine can then be used as a nitrogen donor in the biosynthesis of many compounds, including other amino acids, purines, and pyrimidines. L-glutamine improves nicotinamide adenine dinucleotide (NAD) redox potential.

Mechanism of action

The mechanism of the possible anti-hepatotoxic activity of L-methionine is not entirely clear. It is thought that metabolism of high doses of acetaminophen in the liver lead to decreased levels of hepatic glutathione and increased oxidative stress. L-methionine is a precursor to L-cysteine. L-cysteine itself may have antioxidant activity. L-cysteine is also a precursor to the antioxidant glutathione. Antioxidant activity of L-methionine and metabolites of L-methionine appear to account for its possible anti-hepatotoxic activity. Recent research suggests that methionine itself has free-radical scavenging activity by virtue of its sulfur, as well as its chelating ability. Amino acids are selected for protein synthesis by binding with transfer RNA (tRNA) in the cell cytoplasm. The information on the amino acid sequence of each individual protein is contained in the sequence of nucleotides in the messenger RNA (mRNA) molecules, which are synthesized in the nucleus from regions of DNA by the process of transcription. The mRNA molecules then interact with various tRNA molecules attached to specific amino acids in the cytoplasm to synthesize the specific protein by linking together individual amino acids; this process, known as translation, is regulated by amino acids (e.g., leucine), and hormones. Which specific proteins are expressed in any particular cell and the relative rates at which the different cellular proteins are synthesized, are determined by the relative abundances of the different mRNAs and the availability of specific tRNA-amino acid combinations, and hence by the rate of transcription and the stability of the messages. From a nutritional and metabolic point of view, it is important to recognize that protein synthesis is a continuing process that takes place in most cells of the body. In a steady state, when neither net growth nor protein loss is occurring, protein synthesis is balanced by an equal amount of protein degradation. The major consequence of inadequate protein intakes, or diets low or lacking in specific indispensable amino acids relative to other amino acids (often termed limiting amino acids), is a shift in this balance so that rates of synthesis of some body proteins decrease while protein degradation continues, thus providing an endogenous source of those amino acids most in need. /Protein synthesis/ The mechanism of intracellular protein degradation, by which protein is hydrolyzed to free amino acids, is more complex and is not as well characterized at the mechanistic level as that of synthesis. A wide variety of different enzymes that are capable of splitting peptide bonds are present in cells. However, the bulk of cellular proteolysis seems to be shared between two multienzyme systems: the lysosomal and proteasomal systems. The lysosome is a membrane-enclosed vesicle inside the cell that contains a variety of proteolytic enzymes and operates mostly at acid pH. Volumes of the cytoplasm are engulfed (autophagy) and are then subjected to the action of the protease enzymes at high concentration. This system is thought to be relatively unselective in most cases, although it can also degrade specific intracellular proteins. The system is highly regulated by hormones such as insulin and glucocorticoids, and by amino acids. The second system is the ATP-dependent ubiquitin-proteasome system, which is present in the cytoplasm. The first step is to join molecules of ubiquitin, a basic 76-amino acid peptide, to lysine residues in the target protein. Several enzymes are involved in this process, which selectively targets proteins for degradation by a second component, the proteasome. /Protein degradation/ Methionine dependence, the inability of cells to grow when the amino acid methionine is replaced in culture medium by its metabolic precursor homocysteine, is characteristic of many cancer cell lines and some tumors in situ. Most cell lines proliferate normally under these conditions. The methionine dependent t

Pharmacodynamics

L-Methionine is a principle supplier of sulfur which prevents disorders of the hair, skin and nails; helps lower cholesterol levels by increasing the liver's production of lecithin; reduces liver fat and protects the kidneys; a natural chelating agent for heavy metals; regulates the formation of ammonia and creates ammonia-free urine which reduces bladder irritation; influences hair follicles and promotes hair growth. L-methionine may protect against the toxic effects of hepatotoxins, such as acetaminophen. Methionine may have antioxidant activity.

Mechanism of action

Glycogenic, by L-Proline oxidase in the kidney, it is ring-opened and is oxidized to form L-Glutamic acid. L-Ornithine and L-Glutamic acid are converted to L-Proline via L-Glutamic acid-gamma-semialdehyde. It is contained abundantly in collagen, and is intimately involved in the function of arthrosis and chordae.

Pharmacodynamics

L-Proline is a major amino acid found in cartilage and is important for maintaining youthful skin as well as repair of muscle, connective tissue and skin damage. It is also essential for the immune system, and for necessary balance of this formula. It is an essential component of collagen and is important for proper functioning of joints and tendons. L-Proline is extremely important for the proper functioning of joints and tendons. Helps maintain and strengthen heart muscles.

Mechanism of action

L-Threonine is a precursor to the amino acids glycine and serine. It acts as a lipotropic in controlling fat build-up in the liver. May help combat mental illness and may be very useful in indigestion and intestinal malfunctions. Also, threonine prevents excessive liver fat. Nutrients are more readily absorbed when threonine is present. Amino acids are selected for protein synthesis by binding with transfer RNA (tRNA) in the cell cytoplasm. The information on the amino acid sequence of each individual protein is contained in the sequence of nucleotides in the messenger RNA (mRNA) molecules, which are synthesized in the nucleus from regions of DNA by the process of transcription. The mRNA molecules then interact with various tRNA molecules attached to specific amino acids in the cytoplasm to synthesize the specific protein by linking together individual amino acids; this process, known as translation, is regulated by amino acids (e.g., leucine), and hormones. Which specific proteins are expressed in any particular cell and the relative rates at which the different cellular proteins are synthesized, are determined by the relative abundances of the different mRNAs and the availability of specific tRNA-amino acid combinations, and hence by the rate of transcription and the stability of the messages. From a nutritional and metabolic point of view, it is important to recognize that protein synthesis is a continuing process that takes place in most cells of the body. In a steady state, when neither net growth nor protein loss is occurring, protein synthesis is balanced by an equal amount of protein degradation. The major consequence of inadequate protein intakes, or diets low or lacking in specific indispensable amino acids relative to other amino acids (often termed limiting amino acids), is a shift in this balance so that rates of synthesis of some body proteins decrease while protein degradation continues, thus providing an endogenous source of those amino acids most in need. /Protein synthesis/ The mechanism of intracellular protein degradation, by which protein is hydrolyzed to free amino acids, is more complex and is not as well characterized at the mechanistic level as that of synthesis. A wide variety of different enzymes that are capable of splitting peptide bonds are present in cells. However, the bulk of cellular proteolysis seems to be shared between two multienzyme systems: the lysosomal and proteasomal systems. The lysosome is a membrane-enclosed vesicle inside the cell that contains a variety of proteolytic enzymes and operates mostly at acid pH. Volumes of the cytoplasm are engulfed (autophagy) and are then subjected to the action of the protease enzymes at high concentration. This system is thought to be relatively unselective in most cases, although it can also degrade specific intracellular proteins. The system is highly regulated by hormones such as insulin and glucocorticoids, and by amino acids. The second system is the ATP-dependent ubiquitin-proteasome system, which is present in the cytoplasm. The first step is to join molecules of ubiquitin, a basic 76-amino acid peptide, to lysine residues in the target protein. Several enzymes are involved in this process, which selectively targets proteins for degradation by a second component, the proteasome. /Protein degradation/

Pharmacodynamics

L-Threonine is an essential amino acid that helps to maintain the proper protein balance in the body. It is important for the formation of collagen, elastin, and tooth enamel, and aids liver and lipotropic function when combined with aspartic acid and methionine.

Mechanism of action

Tyrosine is produced in cells by hydroxylating the essential amino acid phenylalanine. This relationship is much like that between cysteine and methionine. Half of the phenylalanine required goes into the production of tyrosine; if the diet is rich in tyrosine itself, the requirements for phenylalanine are reduced by about 50%. The mechanism of L-tyrosine's antidepressant activity can be accounted for by the precursor role of L-tyrosine in the synthesis of the neurotransmitters norepinephrine and dopamine. Elevated brain norepinephrine and dopamine levels are thought to be associated with antidepressant effects.

Pharmacodynamics

Tyrosine is a nonessential amino acid synthesized in the body from phenylalanine. Tyrosine is critical for the production of the body's proteins, enzymes and muscle tissue. Tyrosine is a precursor to the neurotransmitters norepinephrine and dopamine. It can act as a mood elevator and an anti-depressant. It may improve memory and increase mental alertness. Tyrosine aids in the production of melanin and plays a critical role in the production of thyroxin (thyroid hormones). Tyrosine deficiencies are manifested by hypothyroidism, low blood pressure and low body temperature. Supplemental tyrosine has been used to reduce stress and combat narcolepsy and chronic fatigue.