scholarly journals Impact of an oral amino acid provision on Achilles peritendinous amino acid concentrations in young and older adults

2021 ◽  
Author(s):  
Chad C. Carroll ◽  
Samantha Couture ◽  
Dominick O. Farino ◽  
Shivam H. Patel ◽  
Nathan W.C. Campbell ◽  
...  
Keyword(s):  
Older Adults ◽  
Amino Acids ◽  
Amino Acid ◽  
Tendon Tissue ◽  
Amino Acid Consumption ◽  
Oral Consumption ◽  
Acid Consumption ◽  
The Impact ◽  
Amino Acid Concentrations ◽  
Tendon Collagen

ABSTRACTRecent studies have indicated that consumption of amino acid-rich compounds can increase tendon collagen content and enhance biomechanical function. Still, it is not clear as to what extent oral consumption of amino acids alters peritendinous amino acid concentrations. Whether aging alters the delivery of amino acids to tendon tissue after oral consumption is also not known. Using microdialysis, we determined the impact of a single oral essential amino acid bolus on Achilles peritendinous amino acid concentrations in younger (n=7; 27±1 yr.) and older adults (n=6; 68±2 yrs.) over four hours. The peritendinous concentration of all amino acids in the beverage except methionine (p=0.136) and glycine (p=0.087) increased with time (p<0.05). Additionally, the concentrations of glycine and arginine were greater in older adults (p≤0.05). We also accessed the impact of amino acid consumption on peritendinous concentrations of pro-collagen Iα1, a marker of collagen synthesis. Pro-collagen Iα1 tended to change with time (p=0.071) but was not altered age (p=0.226). We demonstrate that an oral amino acid bolus leads to modest increases in Achilles peritendinous amino acid concentrations in young and older adults. The concentration of some amino acids was also greater in older adults. However, the amino acid bolus did not significantly impact peritendinous pro-collagen concentrations.

scholarly journals Effect of 30 % nutrient restriction in the first half of gestation on maternal and fetal baboon serum amino acid concentrations

2012 ◽  
Vol 109 (8) ◽  
pp. 1382-1388 ◽  
Author(s):  
Thomas J. McDonald ◽  
Guoyao Wu ◽  
Mark J. Nijland ◽  
Susan L. Jenkins ◽  
Peter W. Nathanielsz ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Maternal Blood ◽  
Nutrient Restriction ◽  
Adult Disease ◽  
Amino Acid Availability ◽  
Lower Body Weight ◽  
Uterine Growth ◽  
The Impact ◽  
Amino Acid Concentrations

Mechanisms linking maternal nutrient restriction (MNR) to intra-uterine growth restriction (IUGR) and programming of adult disease remain to be established. The impact of controlled MNR on maternal and fetal amino acid metabolism has not been studied in non-human primates. We hypothesised that MNR in pregnant baboons decreases fetal amino acid availability by mid-gestation. We determined maternal and fetal circulating amino acid concentrations at 90 d gestation (90dG, term 184dG) in control baboons fed ad libitum (C, n 8) or 70 % of C (MNR, n 6). Before pregnancy, C and MNR body weights and circulating amino acids were similar. At 90dG, MNR mothers had lower body weight than C mothers (P< 0·05). Fetal and placental weights were similar between the groups. MNR reduced maternal blood urea N (BUN), fetal BUN and fetal BUN:creatinine. Except for histidine and lysine in the C and MNR groups and glutamine in the MNR group, circulating concentrations of all amino acids were lower at 90dG compared with pre-pregnancy. Maternal circulating amino acids at 90dG were similar in the MNR and C groups. In contrast, MNR fetal β-alanine, glycine and taurine all increased. In conclusion, maternal circulating amino acids were maintained at normal levels and fetal amino acid availability was not impaired in response to 30 % global MNR in pregnant baboons. However, MNR weight gain was reduced, suggesting adaptation in maternal–fetal resource allocation in an attempt to maintain normal fetal growth. We speculate that these adaptive mechanisms may fail later in gestation when fetal nutrient demands increase rapidly, resulting in IUGR.

Response of hepatic amino acid consumption to chronic metabolic acidosis

1996 ◽  
Vol 271 (1) ◽  
pp. F198-F202 ◽  
Author(s):  
L. Boon ◽  
P. J. Blommaart ◽  
A. J. Meijer ◽  
W. H. Lamers ◽  
A. C. Schoolwerth
Keyword(s):  
Amino Acids ◽  
Metabolic Acidosis ◽  
Amino Acid ◽  
Fold Increase ◽  
Acid Uptake ◽  
Urea Synthesis ◽  
Chronic Metabolic Acidosis ◽  
Urea Excretion ◽  
Amino Acid Consumption ◽  
Acid Consumption

In a previous paper, we showed that an inhibition of amino acid transport across the liver plasma membrane is responsible for the decrease in urea synthesis in acute metabolic acidosis. We have now studied the mechanism responsible for the decline in urea synthesis in chronic acidosis. Chronic metabolic acidosis and alkalosis were induced by feeding three groups of rats HCl, NH4Cl, and NaHCO3 (8 mmol/day) for 7 days. Amino acids and NH4+ were measured in portal vein, hepatic vein, and aortic plasma, and arteriovenous differences were calculated. The rates of urinary urea and NH4+ excretion were also determined. Hepatic amino acid consumption was lower in both HCl and NH4Cl acidosis compared with NaHCO3-fed rats. Glutamine release was not different in the three conditions. Because intrahepatic concentrations of amino acids and intracellular protein degradation were similar under these conditions, it can be concluded that at low blood pH amino acid catabolism may be inhibited and might explain the observed decrease in urea excretion in HCl, but not NH4Cl, acidosis; urea excretion was comparable in the NH4Cl and NaHCO3 groups presumably because the increased NH4+ load in the former group was processed, uninhibited, to urea. Amino acids not used by the liver in acidosis could account for the 25-fold increase in NH4+ excretion in HCl and NH4Cl compared with alkalosis (P < 0.05). These findings indicate that urea synthesis is decreased in chronic HCl acidosis. They show that urea synthesis is controlled in chronic, as in acute, acidosis by amino acid uptake by the liver and/or intrahepatic degradation and that the ornithine cycle per se has only minor control of acid-base homeostasis.

scholarly journals Rabbit Carcasses for Use in Feline Diets: Amino Acid Concentrations in Fresh and Frozen Carcasses With and Without Gastrointestinal Tracts

2021 ◽  
Vol 7 ◽  
Author(s):  
Tammy J. Owens ◽  
Andrea J. Fascetti ◽  
C. Christopher Calvert ◽  
Jennifer A. Larsen
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Crude Protein ◽  
Protein Body ◽  
National Research Council ◽  
Body Water ◽  
Taurine Supplementation ◽  
Frozen Ground ◽  
Taurine Deficiency ◽  
Amino Acid Concentrations

Whole-prey diets for exotic feline species are common, and this practice has also increased in popularity for domestic cats. However, prior analyses of prey indicate possible essential amino acid inadequacy, and dilated cardiomyopathy from taurine deficiency was reported in cats fed whole ground rabbit. Crude protein, body water, and amino acid concentrations were evaluated in fresh and frozen ground rabbits with (n=10) or without (n = 10) gastrointestinal tracts. Amino acids were greater in fresh samples without gastrointestinal tracts (p &lt; 0.05) except taurine, glycine, and cysteine. When normalized for protein content, only glutamate, alanine, methionine, isoleucine, tyrosine, lysine, histidine, and arginine were greater in fresh rabbits without gastrointestinal tracts (g/16 g N basis; p &lt; 0.05). Freezing at −18°C for 30 days had no effect on crude protein or body water content. After freezing, only methionine was lower and only proline was higher when gastrointestinal tracts were omitted (g/16 g N basis; p &lt; 0.05). Regardless, all essential amino acids except taurine exceeded Association of American Feed Control Officials and National Research Council nutrient recommendations for all feline life stages. In contrast, there was minimal impact of treatment on taurine concentrations. However, although feline taurine requirements for prey and other raw or fresh food diets remain undefined, none of the rabbit samples met any recommendation for taurine concentrations for commercial canned or dry extruded diets, ranging from 20 to 90% of the minimum values. Taurine supplementation is recommended when feeding rabbit to cats. Determination of taurine requirements of cats fed whole-prey diets is warranted.

scholarly journals Metabolic characterization of the bovine blastocyst, inner cell mass, trophectoderm and blastocoel fluid

Reproduction ◽  
2003 ◽  
pp. 299-308 ◽  
Author(s):  
N Gopichandran ◽  
HJ Leese
Keyword(s):  
Amino Acids ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Lactate Production ◽  
Cell Populations ◽  
Lower Glucose ◽  
Amino Acid Consumption ◽  
Production And Consumption ◽  
Acid Consumption

The formation of a viable blastocyst is dependent upon the establishment of a correct inner cell mass (ICM):trophectoderm cell ratio but little is known about the metabolism of the two cell populations or about the composition of blastocoel fluid. In this study, the metabolism of intact bovine blastocysts, isolated ICM and trophectoderm was examined in terms of glucose and pyruvate uptake, lactate production, and amino acid consumption or production. The concentration of these nutrients in blastocoel fluid was also determined. The metabolism of glucose, pyruvate and lactate differed significantly between the isolated ICM and trophectoderm. Isolated trophectoderm had a higher pyruvate (P<0.001) and lower glucose (P<0.05) consumption, and higher lactate production (P<0.05) than did ICM. The consumption or production of amino acids by ICM and trophectoderm also differed, with the trophectoderm displaying a higher turnover (the sum of production and consumption). The ICM and trophectoderm both depleted arginine, aspartate and leucine, whereas the production of alanine was consistent. Isolated ICM depleted a further six amino acids, which appeared during trophectoderm culture; the reverse trend was observed for the remaining amino acids. The concentration of lactate in blastocoel fluid was significantly higher than in synthetic oviductal fluid supplemented with amino acids and BSA (SOFaaBSA; P<0.05). However, glucose (P<0.05) and pyruvate (P<0.001) concentrations were both lower. Aspartate, glutamate, glycine, alanine and tryptophan were present at significantly higher concentrations in blastocoel fluid than in SOFaaBSA, whereas threonine and asparagine concentrations were significantly lower. The metabolism of composite blastocysts, obtained by summing the consumption and production profiles of the ICM and trophectoderm, and taking into account their respective number of cells, was higher than that of intact blastocysts, indicating that upon isolation of the two cell populations there may be disruption to paracrine interactions or the onset of culture-induced cellular stress or both.

scholarly journals An Intracellular Ammonium Transporter Is Necessary for Replication, Differentiation, and Resistance to Starvation and Osmotic Stress in Trypanosoma cruzi

mSphere ◽  
2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Teresa Cruz-Bustos ◽  
Evgeniy Potapenko ◽  
Melissa Storey ◽  
Roberto Docampo
Keyword(s):  
Life Cycle ◽  
Amino Acid ◽  
Osmotic Stress ◽  
Trypanosoma Cruzi ◽  
Etiologic Agent ◽  
Ammonium Transporter ◽  
Amino Acid Consumption ◽  
Acid Consumption ◽  
Acidic Compartments ◽  
Production Of Ammonia

Trypanosoma cruzi is an important human and animal pathogen and the etiologic agent of Chagas disease. The parasite undergoes drastic changes in its metabolism during its life cycle. Amino acid consumption becomes important in the infective stages and leads to the production of ammonia (NH3), which needs to be detoxified. We report here the identification of an ammonium (NH4 +) transporter that localizes to acidic compartments and is important for replication, differentiation, and resistance to starvation and osmotic stress.

Uptake and metabolism of amino acids by the dog liver perfused in situ

1962 ◽  
Vol 202 (3) ◽  
pp. 407-414 ◽  
Author(s):  
Rapier H. McMenamy ◽  
William C. Shoemaker ◽  
Jonas E. Richmond ◽  
David Elwyn
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Sharp Rise ◽  
Dog Blood ◽  
Dog Liver ◽  
Amino Acid Concentrations ◽  
Uptake And Metabolism

Dog livers were perfused in situ for periods up to 6 hr with dog blood recycled through a pump-oxygenator. An amino acid mixture was administered for 90 min. Concentrations of amino acids were determined at intervals of 30 min or more. Rates of uptake and metabolism were calculated. After the start of perfusion, there is a fall in most plasma amino acid concentrations and a reciprocal rise in liver amino acids. Addition of amino acids causes a sharp rise in plasma amino acids. There is a rapid uptake of most of the amino acids by liver, although the concentrations of amino acids in liver fail to rise appreciably. Notable exceptions are valine, leucine, and isoleucine. Uptake of amino acids stimulates: a) an increase in the rate of synthesis of urea which ultimately accounts for 90% of the metabolized amino acids; b) a net synthesis of ornithine; and c) net noncatabolic metabolism of amino acids which may in part be protein synthesis. The results support the view that the liver temporarily stores a part of ingested amino acids as proteins, and subsequently makes them available to other organs.

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