Amino acid balance and food intake: effect of previous diet on plasma amino acids

Cells have a constant turnover of proteins that recycle most amino acids over time. Net loss is mainly due to amino acid oxidation. Homeostasis is achieved through exchange of essential amino acids with non-essential amino acids and the transfer of amino groups from oxidised amino acids to amino acid biosynthesis. This homeostatic condition is maintained through an active mTORC1 complex. Under amino acid depletion, mTORC1 is inactivated. This increases the breakdown of cellular proteins through autophagy and reduces protein biosynthesis. The general control non-derepressable 2/ATF4 pathway may be activated in addition, resulting in transcription of genes involved in amino acid transport and biosynthesis of non-essential amino acids. Metabolism is autoregulated to minimise oxidation of amino acids. Systemic amino acid levels are also tightly regulated. Food intake briefly increases plasma amino acid levels, which stimulates insulin release and mTOR-dependent protein synthesis in muscle. Excess amino acids are oxidised, resulting in increased urea production. Short-term fasting does not result in depletion of plasma amino acids due to reduced protein synthesis and the onset of autophagy. Owing to the fact that half of all amino acids are essential, reduction in protein synthesis and amino acid oxidation are the only two measures to reduce amino acid demand. Long-term malnutrition causes depletion of plasma amino acids. The CNS appears to generate a protein-specific response upon amino acid depletion, resulting in avoidance of an inadequate diet. High protein levels, in contrast, contribute together with other nutrients to a reduction in food intake.

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Dietary intake of tryptophan tied emotion-related impulsivity in humans

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000608 ◽

2019 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Florian Javelle ◽

Descartes Li ◽

Philipp Zimmer ◽

Sheri L. Johnson

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Food Intake ◽

Essential Amino Acid ◽

Food Habits ◽

Psychological Disorder ◽

Serotonin Synthesis ◽

Amino Acid Tryptophan ◽

Pass Through ◽

Three Factor

Abstract. Emotion-related impulsivity, defined as the tendency to say or do things that one later regret during periods of heightened emotion, has been tied to a broad range of psychopathologies. Previous work has suggested that emotion-related impulsivity is tied to an impaired function of the serotonergic system. Central serotonin synthesis relies on the intake of the essential amino acid, tryptophan and its ability to pass through the blood brain barrier. Objective: The aim of this study was to determine the association between emotion-related impulsivity and tryptophan intake. Methods: Undergraduate participants (N = 25, 16 women, 9 men) completed a self-rated measure of impulsivity (Three Factor Impulsivity Index, TFI) and daily logs of their food intake and exercise. These data were coded using the software NutriNote to evaluate intakes of tryptophan, large neutral amino acids, vitamins B6/B12, and exercise. Results: Correlational analyses indicated that higher tryptophan intake was associated with significantly lower scores on two out of three subscales of the TFI, Pervasive Influence of Feelings scores r = –.502, p < . 010, and (lack-of) Follow-Through scores, r = –.407, p < . 050. Conclusion: Findings provide further evidence that emotion-related impulsivity is correlated to serotonergic indices, even when considering only food habits. It also suggests the need for more research on whether tryptophan supplements might be beneficial for impulsive persons suffering from a psychological disorder.

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CIRCADIAN PERIODICITY OF BLOOD AMINO ACIDS IN THE NEONATE

PEDIATRICS ◽

10.1542/peds.45.5.782 ◽

1970 ◽

Vol 45 (5) ◽

pp. 782-791

Author(s):

Ralph D. Feigin ◽

Morey W. Haymond

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Detailed Analysis ◽

Normal Values ◽

Time Of Day ◽

Plasma Amino Acids ◽

Older Children ◽

Total Blood ◽

Term Infants ◽

Plasma Tyrosine

Blood amino acids were obtained every 4 hours for 24 hours from 46 full-term infants who were between 1 hour and 120 hours of age when first sampled. Blood was also obtained at 0400 and 1200 hours on the same day from 10 additional infants, aged 48 to 72 hours at the time of study, for more detailed analysis of individual blood amino acids. Periodicity of total blood amino acids was demonstrated as early as the first day of life in some infants. This blood amino acid rhythmicity was similar but not identical to that previously observed in adults and older children. Concentrations of blood amino acids were minimal at 0400 hours and peaked between 1200 and 2000 hours. Periodicity of individual blood amino acids was similar to that for total blood amino acids but much less consistent. The presence of periodicity for plasma tyrosine was demonstrable even in two patients with neonatal tyrosinemia. Since plasma amino acids vary normally as a function of time, "normal values" must be standardized for time of day.

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The Amino Acid Need for Milk Synthesis Is Defined by the Maximal Uptake of Plasma Amino Acids by Porcine Mammary Glands

Journal of Nutrition ◽

10.1093/jn/134.9.2182 ◽

2004 ◽

Vol 134 (9) ◽

pp. 2182-2190 ◽

Cited By ~ 9

Author(s):

Xinfu Guan ◽

Brian J. Bequette ◽

Pao K. Ku ◽

Robert J. Tempelman ◽

Nathalie L. Trottier

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Mammary Glands ◽

Plasma Amino Acids

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DESIGNING BALANCED FEEDS FOR INDUSTRIAL AQUACULTURE USING PROTEIN HYDROLYSATES OF FISH BY-PASS RAW MATERIALS

Fisheries ◽

10.37663/0131-6184-2021-4-81-88 ◽

2021 ◽

Vol 2021 (4) ◽

pp. 81-88

Author(s):

Olga Mezenova ◽

Dmitriy Pyanov ◽

Svetlana Agafonova ◽

Natalia Mezenova ◽

V. Volkov

Keyword(s):

Amino Acids ◽

Molecular Weight ◽

Amino Acid ◽

Raw Materials ◽

Protein Hydrolysates ◽

Total Protein Content ◽

Alternative Sources ◽

Amino Acid Balance ◽

Limiting Amino Acids ◽

By Products

The perspective of the production of domestic compound feed for the development of industrial aquaculture in Russia is shown. Alternative sources of protein in mixed fodder for salmon and sturgeon have been investigated. The advantages of using protein hydrolysates instead of a part of fishmeal in compound feed are described. The advantages of protein hydrolysates from fish by-products are considered, the chemical composition and molecular fractional composition of sublimated protein hydrolysates obtained by enzymatic and thermal pathways from sardinella scales and ridges are studied. The presence in hydrolysates of 53.3 - 97.7% of low molecular weight peptides with a molecular weight of less than 10 kDa with a total protein content of 80.8-94.1% was established. Indicators of amino acid balance (scor) of hydrolyzates of scales and ridges of sardinella were calculated in relation to the established requirements for amino acids in salmonids. Indicators of amino acid balance (scor) of hydrolyzates of scales and ridges of sardinella were calculated in relation to the established requirements for amino acids in salmonids.It was found that the introduction of an enzymatically obtained hydrolyzate is more favorable for an increase in the content of limiting amino acids in mixed feed, and the use of sardinella scales for hydrolysis is more preferable than its ridges.

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Source and function of urinary ammonia in the alligator

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1959.197.4.873 ◽

1959 ◽

Vol 197 (4) ◽

pp. 873-879 ◽

Cited By ~ 26

Author(s):

Roland A. Coulson ◽

Thomas Hernandez

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Acid Level ◽

Amino Acid Level ◽

Plasma Amino Acid ◽

Plasma Amino Acids ◽

Renal Reabsorption ◽

And Function ◽

Phosphate Solutions

The rate of renal deamination of 18 amino acids was determined by injecting them into alligators and measuring the ammonia excreted. Not only did glycine, alanine, glutamine and leucine account for nearly half of the plasma amino acids, they were also deaminated more rapidly than any of the others. In view of this it was concluded that these four amino acids are the natural precursors of urinary NH3 in the alligator. Increased NH3 and CO2 excretion following glycine injections resulted in increased renal reabsorption of Na and Cl when NaCl was injected and increased Na reabsorption when NaHCO3 or Na phosphate solutions were injected. The fact that excess NH4HCO3 excretion enhances salt reabsorption independent of plasma pH makes it probable that the excretion of N is the chief function of the ammonia mechanism and that salt conservation is incidental. Insulin decreased the plasma amino acid level and drastically reduced the NH3 excretion. With the decrease in ammonia, NaCl and NaHCO3 were excreted in increased amounts.

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