Influence of hyperinsulinaemia on intracellular amino acid levels and amino acid exchange across splanchnic and leg tissues in uraemia

1988 ◽  
Vol 74 (2) ◽  
pp. 155-163 ◽  
Author(s):  
Anders Alvestrand ◽  
Ralph A. Defronzo ◽  
Douglas Smith ◽  
John Wahren
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plasma Concentrations ◽  
Amino Acid Exchange ◽  
Control Subjects ◽  
Intracellular Amino Acid ◽  
Resistance To Insulin ◽  
And Control ◽  
Amino Acid Concentrations ◽  
Acid Exchange

1. To examine whether insulin resistance in uraemia extends to amino acid metabolism, the effect of physiological hyperinsulinaemia on plasma amino acid concentrations was studied in 17 chronically uraemic and 28 healthy subjects by using the euglycaemic insulin clamp technique. 2. In six uraemic and seven control subjects, splanchnic and leg exchange of amino acids was quantified with hepatic and femoral venous catheterization, and in five uraemic and eight control subjects intracellular free amino acid concentrations were determined in muscle tissue obtained by needle biopsy. 3. In response to hyperinsulinaemia the plasma concentrations of all amino acids except alanine decreased by 10–50% in both uraemic and control subjects. Splanchnic alanine uptake declined by 20% and leg amino acid release tended to decrease in both groups. 4. The intracellular levels of all measured amino acids except alanine fell significantly and to a similar extent in uraemic and control subjects. 5. These results indicate that insulin-mediated alterations in regional amino acid exchange and in plasma and intracellular amino acid concentrations are similar in uraemic and control subjects. 6. It is concluded that tissue insensitivity to insulin in uraemia does not extend to uptake or release of amino acids and that resistance to insulin can be selective in its effect on different metabolic functions.

Changes in plasma amino acid concentrations in response to HIV-1 infection

1994 ◽  
Vol 40 (5) ◽  
pp. 785-789 ◽  
Author(s):  
G L Hortin ◽  
M Landt ◽  
W G Powderly
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plasma Concentrations ◽  
Infected Group ◽  
Control Subjects ◽  
Immunodeficiency Virus ◽  
Amino Acid Profiles ◽  
Amino Acid Concentrations ◽  
Hiv 1

Abstract Plasma concentrations of 21 amino acids were determined for 20 control subjects and 20 subjects infected with human immunodeficiency virus type 1 (HIV). Compared with the control subjects, the HIV-infected group had lower cystine, tryptophan, and methionine (decreased 67%, 52%, and 32%, respectively, P < 0.001 for each) and increased taurine (230%, P < 0.001) and lysine concentrations (30%, P < 0.001). Other amino acid concentrations changed modestly. Amounts of cystine, tryptophan, methionine, taurine, and lysine did not differ significantly between subgroups of HIV-infected subjects with > 200 (n = 6) or < 200 (n = 14) CD4+ lymphocytes per microliter, suggesting that the concentrations decrease soon after infection and change little thereafter. Activation of metabolism of cystine to taurine may explain reciprocal changes in these amino acids and known depletion of cystine and glutathione. The selective changes in amino acid profiles observed during HIV infection differ from those recognized for malnutrition or other pathological processes.

Intravenous Infusion of α-Oxoisocaproate: Influence on Amino Acid and Nitrogen Metabolism in Patients with Liver Cirrhosis

1982 ◽  
Vol 62 (3) ◽  
pp. 285-293 ◽  
Author(s):  
L. S. Eriksson ◽  
L. Hagenfeldt ◽  
J. Wahren
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Intravenous Infusion ◽  
Aromatic Amino Acids ◽  
Control Subjects ◽  
Catheter Technique ◽  
Healthy Control ◽  
And Control ◽  
The Brain ◽  
Amino Acid Concentrations

1. The metabolic effect of α-oxoisocaproate (4-methyl-2-oxovalerate) infusion was examined in six patients with cirrhosis and in nine healthy control subjects. The arterial concentrations of amino acids, urea, ammonia, insulin and catecholamines were determined in the basal state and during intravenous infusion of α-oxoisocaproate (300 μmol/min) for 150 min. The exchanges of amino acids and substrates across the splanchnic region, the brain and the leg were examined in the healthy subjects by a catheter technique. 2. Basal α-oxoisocaproate levels were similar in patients and control subjects. During infusion the concentrations of α-oxoisocaproate rose to 90–130 μmol/l; they were 20–35% lower in the patients. Arterial leucine concentration increased in both groups to 250–300 μmol/l. Valine and isoleucine concentrations decreased (50–60%) as did to a lesser extent the concentrations of aromatic amino acids and methionine. 3. Regional exchange of amino acids was not significantly influenced by α-oxoisocaproate infusion. Arterial urea concentration decreased (12%, P < 0.05) and ammonia levels rose (15–25%, P < 0.05) in both groups. In the patients both adrenaline (100%, P < 0.001) and noradrenaline concentrations were elevated (350%, P < 0.001) in the basal state; insulin levels were similar to those in control subjects. 4. It is concluded that α-oxoisocaproate is rapidly transaminated to leucine in patients with cirrhosis and in healthy control subjects. α-Oxoisocaproate infusion resembles leucine infusion in its influence on aromatic amino acid concentrations, but in addition it elicits increased ammonia levels and decreased urea formation.

Interactions of neutral and acidic amino acids in renal tubular transport

1962 ◽  
Vol 202 (3) ◽  
pp. 577-583 ◽  
Author(s):  
William A. Webber
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plasma Concentrations ◽  
Side Chain ◽  
Neutral Amino Acids ◽  
Acidic Amino Acids ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular Transport ◽  
Renal Tubular ◽  
Amino Acid Concentrations

The effects of intravenous infusions of a variety of neutral and acidic amino acids on the plasma concentrations and excretions of naturally occurring amino acids were studied in dogs. Conventional clearance techniques were used, and the amino acid concentrations were determined by ion exchange column chromatography. Infusion of either l-glutamic acid or l-aspartic acid caused a gross increase in the plasma concentration and excretion of the other. Infusions of neutral amino acids including glycine, l-alanine, l-leucine, l-methionine, l-proline, and l-phenylalanine caused some minor changes in the endogenous plasma amino acid concentrations. They produced increases in the excretion of other neutral amino acids and, in some cases, of acidic and basic amino acids as well. In general, amino acids with long side chains were most effective in inhibiting reabsorption while cyclic side-chain compounds were less effective. There appear to be at least three somewhat separable mechanisms for renal tubular reabsorption of amino acids in dogs.

scholarly journals Renal metabolism of amino acids: its role in interorgan amino acid exchange

2004 ◽  
Vol 79 (2) ◽  
pp. 185-197 ◽  
Author(s):  
Marcel CG van de Poll ◽  
Peter B Soeters ◽  
Nicolaas EP Deutz ◽  
Kenneth CH Fearon ◽  
Cornelis HC Dejong
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Exchange ◽  
Renal Metabolism ◽  
Acid Exchange

scholarly journals Changes of amino acid concentrations in Polish Merino sheep between 21 and 150 days of life

2014 ◽  
Vol 59 (No. 2) ◽  
pp. 68-75
Author(s):  
MR Tatara ◽  
A. Brodzki ◽  
K. Pasternak ◽  
M. Szpetnar ◽  
P. Rosenbeiger ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plasma Concentrations ◽  
Exchange Chromatography ◽  
Plasma Amino Acid ◽  
Merino Sheep ◽  
Amino Acid Profiles ◽  
Systemic Development ◽  
Positive Correlations ◽  
Amino Acid Concentrations

The aim of this study was to evaluate plasma amino acid profiles and their interrelationships in male Polish Merino sheep at two different stages of their systemic development &ndash; at the neonatal monogastric stage and as a fully grown ruminant. Male lambs (n = 12, singles) were kept indoors in pens under standard rearing conditions and weaned at the age of 10 weeks of life. Blood samples were collected on day 21 and 150 of life. Free amino acids were determined in plasma using ion-exchange chromatography. There was a significant reduction in plasma amino acid concentrations between neonatal and functioning ruminants for threonine, serine, glutamate, proline, citrulline, tyrosine, tryptophan, lysine, histidine and arginine. Significant increases in the plasma concentrations of alpha-amino-butyrate and isoleucine were observed in 150 day old lambs. Except for glutamine in 21 day old sheep which was significantly negatively correlated with serine, glutamate, proline and tyrosine concentrations in plasma, the obtained results in younger and older groups of lambs showed 47 and 22 significant positive correlations between the evaluated amino acids. This study shows that decreases in plasma amino acid concentrations in 150 day old sheep with physiologically developed forestomachs are dominant in comparison to 21 day-old animals receiving maternal milk as a basic diet. Our results address the possibility of utilising improved amino acid supply for growing lambs with developed forestomachs. &nbsp;

scholarly journals Concentrations of amino acids and urea in the plasma of the ruminating calf and estimation of the amino acid requirements

1974 ◽  
Vol 32 (2) ◽  
pp. 421-433 ◽  
Author(s):  
A. P. Williams ◽  
R. H. Smith
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Dry Matter ◽  
Plasma Concentrations ◽  
Live Weight ◽  
Progressive Increase ◽  
Protein Supplement ◽  
Individual Amino Acid ◽  
Rate Of Increase ◽  
Amino Acid Concentrations

1. A study was made of factors affecting the plasma concentrations of free amino acids (PAA) and urea (PU) in calves receiving approximately equal daily amounts of concentrates (flaked maize and protein supplements) and straw, the former at 10.00 and 17.00 hours, the latter at 17.00 hours only.2. For calves receiving a diet containing 20 g nitrogen/kg dry matter in which the protein supplement was decorticated, extracted groundnut meal (DCGM) (diet A) there were marked increases in PAA and PU about 1–2 h after a morning feed, then a fall in these values 2 h later to a level which was maintained for the next 3 h. No similar changes occurred after the evening feed. Samples taken 3 h after the morning feed were used in subsequent comparative experiments. There was much more variation between animals than within animals in total PAA, PU and the concentrations of most individual amino acids in these samples.3. Total PAA and most individual amino acid concentrations were not appreciably affected when the DCGM intake was reduced to give 10 g N/kg dry matter in the diet (diet C), but PU was halved. When maize gluten replaced DCGM as the protein supplement at the higher N intake (diet B) then PU doubled, but again total PAA and most individual amino acid concentrations were little affected. Exceptions were arginine, which was halved, and leucine, which was doubled.4. Infusions of more than 4·4 g L-methionine/d into the abomasums of calves (110–160 kg live weight) receiving diet A led to a marked increase in plasma methionine concentration. This was considered to correspond with the point at which methionine requirements were met. Using a chromic oxide marker to estimate flows of methionine and cystine from the rumen to the duodenum, it was calculated that under these conditions the methionine requirement was 9·8 g/d, with a cystine flow of 4·9 g/d. Similar calculations showed the corresponding value to be 7·5 g/d with a cystine flow of 2·8 g/d for calves receiving diet C.5. Infusion of increasing levels of L-lysine into the abomasums of calves (110–160 kg live weight) receiving diet B led to a progressive increase in plasma lysine concentration. There was no consistent change in the rate of increase with increasing amounts infused. Estimated lysine requirement appeared therefore to be less than the flow of lysine from the rumen to the duodenum under these conditions (18·8 g/d).

Effect of protein intake on weight gain and plasma amino acid levels in uremic rats

1976 ◽  
Vol 230 (5) ◽  
pp. 1455-1459 ◽  
Author(s):  
M Wang ◽  
I Vyhmeister ◽  
JD Kopple ◽  
ME Swendseid
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Intake ◽  
Plasma Concentrations ◽  
Plasma Amino Acid ◽  
Uremic Patient ◽  
Lower Protein ◽  
Similar Weight ◽  
Amino Acid Levels ◽  
And Control

Chronically uremic rats weighing approximately 180-200 g and sham-operated controls of similar weight were pair fed diets containing 5, 15 or 23% protein for 10-12 wk. At each level of protein intake, uremic animals gained less weight and had lower protein efficiency ratios than controls. In addition, certain plasma amino acid levels were altered in the uremic animals. These included tyrosine and the tyrosine/phenylalanine ratio, which were decreased, and citrulline, glycine, and the methylhistidines, which were increased. In both uremic and control rats, plasma concentrations of certain amino acids, primarily nonessential ones, varied inversely with protein intake; with the 5% protein diet, the ratio of essential to nonessential amino acids was significantly reduced. These observations indicate that both uremia and reduced protein intake may affect growth and amino acid metabolism in rats with chronic renal failure. The finding that uremic rats utilize protein less efficiently may indicate that marked reductions in protein intake may be particularly hazardous to the nutritional status of the uremic patient.

Insulin and hyperaminoacidemia regulate by a different mechanism leucine turnover and oxidation in obesity

1996 ◽  
Vol 270 (2) ◽  
pp. E273-E281 ◽  
Author(s):  
L. Luzi ◽  
P. Castellino ◽  
R. A. DeFronzo
Keyword(s):  
Insulin Resistance ◽  
Amino Acids ◽  
Amino Acid ◽  
Protein Metabolism ◽  
Plasma Amino Acid ◽  
Total Plasma ◽  
Control Subjects ◽  
Insulin Clamp ◽  
High Amino Acid ◽  
And Control

Seven normal glucose-tolerant obese subjects [ideal body weight (IBW) = 161%] and 18 controls (IBW = 102%) were studied with the euglycemic insulin clamp (10 and 40 mU.m-2.min-1) technique, [14C]leucine infusion, and indirect calorimetry to examine if the insulin resistance with respect to glucose metabolism extends to amino acid/protein metabolism. In the basal state, total plasma amino acid and leucine concentrations, endogenous leucine flux (ELF), leucine oxidation (LO), and nonoxidative leucine disposal (NOLD) were similar in obese and control subjects. During both low (10 mU.m-2.min-1)- and higher (40 mU.m-2.min-1)-dose insulin clamp studies, insulin-mediated glucose uptake was reduced in obese vs. control subjects (P < 0.01). During the last hour of the higher-dose insulin clamp step, the decrease in total plasma amino acids, branched-chain amino acids, and leucine concentration was impaired in obese vs. control subjects (P < 0.01). However, suppression of ELF and NOLD was similar in both groups. During the low-dose insulin clamp, the decrease in plasma leucine concentration, LO, and ELF all were impaired (P < 0.01). A second study was performed in which the total plasma amino acid concentration was increased two- to threefold in both groups. Under these conditions of low plasma insulin/high amino acid levels, LO and NOLD increased similarly in obese and control subjects. In conclusion, insulin resistance is a common feature of both glucose and protein metabolism in obesity. The defect in protein metabolism is characterized by an impairment of the ability of insulin to inhibit proteolysis; the stimulatory effect of hyperaminoacidemia on protein synthesis is intact in obesity.

scholarly journals Progress towards reduced-crude protein diets for broiler chickens and sustainable chicken-meat production

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sonia Yun Liu ◽  
Shemil P. Macelline ◽  
Peter V. Chrystal ◽  
Peter H. Selle
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Broiler Chickens ◽  
Crude Protein ◽  
Plasma Concentrations ◽  
Essential Amino Acids ◽  
Chicken Meat ◽  
Meat Production ◽  
Accurate Identification ◽  
Reduced Crude Protein

AbstractThe prime purpose of this review is to explore the pathways whereby progress towards reduced-crude protein (CP) diets and sustainable chicken-meat production may be best achieved. Reduced-CP broiler diets have the potential to attenuate environmental pollution from nitrogen and ammonia emissions; moreover, they have the capacity to diminish the global chicken-meat industry’s dependence on soybean meal to tangible extents. The variable impacts of reduced-CP broiler diets on apparent amino acid digestibility coefficients are addressed. The more accurate identification of amino acid requirements for broiler chickens offered reduced-CP diets is essential as this would diminish amino acid imbalances and the deamination of surplus amino acids. Deamination of amino acids increases the synthesis and excretion of uric acid for which there is a requirement for glycine, this emphasises the value of so-called “non-essential” amino acids. Starch digestive dynamics and their possible impact of glucose on pancreatic secretions of insulin are discussed, although the functions of insulin in avian species require clarification. Maize is probably a superior feed grain to wheat as the basis of reduced-CP diets; if so, the identification of the underlying reasons for this difference should be instructive. Moderating increases in starch concentrations and condensing dietary starch:protein ratios in reduced-CP diets may prove to be advantageous as expanding ratios appear to be aligned to inferior broiler performance. Threonine is specifically examined because elevated free threonine plasma concentrations in birds offered reduced-CP diets may be indicative of compromised performance. If progress in these directions can be realised, then the prospects of reduced-CP diets contributing to sustainable chicken-meat production are promising.

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