Effect of cationic amino acid infusion on potassium metabolism in vivo

1964 ◽  
Vol 206 (2) ◽  
pp. 403-408 ◽  
Author(s):  
Herbert W. Dickerman ◽  
W. Gordon Walker
Keyword(s):  
Amino Acid ◽  
Tubular Secretion ◽  
Potassium Excretion ◽  
Acid Infusion ◽  
Cationic Amino Acid ◽  
Amino Acid Infusion ◽  
Cationic Amino Acids ◽  
K Secretion ◽  
Filtered Load

The infusion of the cationic amino l-lysine, l-arginine, or l-ornithine into dogs regularly increases potassium excretion to levels that exceed the filtered load of potassium. Hyperkalemia occurs during the amino acid infusion as a result of displacement of the intracellular potassium by the cationic amino acids. This rise in plasma K is not necessary for the stimulation of K secretion since infusion of the lysine directly into the renal artery produces K secretion without significant change in plasma K. This increased potassium excretion is promptly suppressed by the administration of thiomerin. The effects upon renal K handling in these experiments appear to be the result of facilitation of tubular secretion of K rather than inhibition of reabsorption.

scholarly journals Amino acid infusion increases the sensitivity of muscle protein synthesis in vivo to insulin. Effect of branched-chain amino acids

1988 ◽  
Vol 254 (2) ◽  
pp. 579-584 ◽  
Author(s):  
P J Garlick ◽  
I Grant
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Branched Chain Amino Acids ◽  
Acid Infusion ◽  
Amino Acid Infusion ◽  
Branched Chain

Rates of muscle protein synthesis were measured in vivo in tissues of post-absorptive young rats that were given intravenous infusions of various combinations of insulin and amino acids. In the absence of amino acid infusion, there was a steady rise in muscle protein synthesis with plasma insulin concentration up to 158 mu units/ml, but when a complete amino acids mixtures was included maximal rates were obtained at 20 mu units/ml. The effect of the complete mixture could be reproduced by a mixture of essential amino acids or of branched-chain amino acids, but not by a non-essential mixture, alanine, methionine or glutamine. It is concluded that amino acids, particularly the branched-chain ones, increase the sensitivity of muscle protein synthesis to insulin.

Response of rat heart and skeletal muscle protein in vivo to insulin and amino acid infusion

1993 ◽  
Vol 264 (6) ◽  
pp. E958-E965 ◽  
Author(s):  
P. H. McNulty ◽  
L. H. Young ◽  
E. J. Barrett
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Skeletal Muscle Protein ◽  
Acid Infusion ◽  
Amino Acid Infusion

Whether insulin, at physiological concentrations, stimulates net muscle protein synthesis in vivo remains unresolved. To examine this, we infused either saline, insulin (2.8 mU.kg-1.min-1, euglycemic clamp), an amino acid solution, or insulin plus amino acids for 4 h into awake overnight-fasted rats. Heart and skeletal muscle protein synthesis was measured by either a continuous tracer infusion method, using L-[1-14C]leucine, L-[2,5-3H]leucine, or L-[ring-2,6-3H]phenylalanine or by injection of L-[ring-2,6-3H]phenylalanine with a pool-flooding bolus of unlabeled phenylalanine. In heart, synthesis rates obtained using the arterial plasma specific activity of [3H]phenylalanine administered as either a tracer infusion or flooding bolus were comparable in saline-treated rats (range 10.9 +/- 1.2 to 12.2 +/- 0.9%/day) and were not affected by infusion of insulin or amino acids. Estimates using continuous infusion of L-[1-14C]leucine were significantly lower (P < 0.001), except when unlabeled amino acids were given also. In skeletal muscle, rates estimated using the flooding bolus (6.7 +/- 0.8%/day) were also not affected by insulin or amino acids. Estimates using continuous infusion of [3H]leucine (2.6 +/- 0.3%/day) or [3H]phenylalanine (2.8 +/- 1.0%/day) were lower and were still lower using [14C]leucine (1.6 +/- 0.6%/day), but increased toward those estimated with the flooding bolus during amino acid infusion. We conclude that, in heart muscle of the mature rat in vivo, neither insulin nor amino acids affect protein synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino acids regulate skeletal muscle PHAS-I and p70 S6-kinase phosphorylation independently of insulin

2000 ◽  
Vol 279 (2) ◽  
pp. E301-E306 ◽  
Author(s):  
W. Long ◽  
L. Saffer ◽  
L. Wei ◽  
E. J. Barrett
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Rat Skeletal Muscle ◽  
S6 Kinase ◽  
Acid Infusion ◽  
P70 S6 Kinase ◽  
Amino Acid Infusion

Refeeding reverses the muscle protein loss seen with fasting. The physiological regulators and cellular control sites responsible for this reversal are incompletely defined. Phosphorylation of phosphorylated heat-acid stabled protein (PHAS-I) frees eukaryotic initiation factor 4E (eIF4E) and stimulates protein synthesis by accelerating translation initiation. Phosphorylation of p70 S6-kinase (p70S6k) is thought to be involved in the regulation of the synthesis of some ribosomsal proteins and other selected proteins with polypyrimidine clusters near the transcription start site. We examined whether phosphorylation of PHAS-I and p70S6k was increased by feeding and determined the separate effects of insulin and amino acids on PHAS-I and p70S6k phosphorylation in rat skeletal muscle in vivo. Muscle was obtained from rats fed ad libitum or fasted overnight ( n = 5 each). Other fasted rats were infused with insulin (3 μU · min−1 · kg−1, euglycemic clamp), amino acids, or the two combined. Gastrocnemius was freeze-clamped, and PHAS-I and p70S6k phosphorylation was measured by quantifying the several phosphorylated forms of these proteins seen on Western blots. We observed that feeding increased phosphorylation of both PHAS-I and p70S6k ( P < 0.05). Infusion of amino acids alone reproduced the effect of feeding. Physiological hyperinsulinemia increased p70S6K ( P< 0.05) but not PHAS-I phosphorylation ( P = 0.98). Addition of insulin to amino acid infusion was no more effective than amino acids alone in promoting PHAS-I and p70S6kphosphorylation. We conclude that amino acid infusion alone enhances the activation of the protein synthetic pathways in vivo in rat skeletal muscle. This effect is not dependent on increases in plasma insulin and simulates the activation of protein synthesis that accompanies normal feeding.

Kidney hemodynamics after ketone body and amino acid infusion in normal and IDDM subjects

Diabetes ◽  
1989 ◽  
Vol 38 (1) ◽  
pp. 75-83 ◽  
Author(s):  
R. Nosadini ◽  
R. Trevisan ◽  
P. Fioretto ◽  
A. Semplicini ◽  
B. Sama ◽  
...  
Keyword(s):  
Amino Acid ◽  
Ketone Body ◽  
Acid Infusion ◽  
Amino Acid Infusion

scholarly journals Effect of Insulin with Concurrent Amino Acid Infusion on Protein Metabolism in Rapidly Growing Pubertal Children with Type 1 Diabetes

2005 ◽  
Vol 58 (2) ◽  
pp. 229-234 ◽  
Author(s):  
Mushtaq A Godil ◽  
Thomas A Wilson ◽  
Peter J Garlick ◽  
Margaret A McNurlan
Keyword(s):  
Type 1 Diabetes ◽  
Amino Acid ◽  
Protein Metabolism ◽  
Acid Infusion ◽  
Amino Acid Infusion

Cationic Amino Acid Transporter-1 (CAT-1) Promotes Fibroblast-Like Synoviocytes Proliferation and Cytokine Secretion by Taking Up L-Arginine in Rheumatoid Arthritis

2021 ◽  
Author(s):  
Ying Lu ◽  
Chongbo Hao ◽  
Shanshan Yu ◽  
Zuan Ma ◽  
Xuelian Fu ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Amino Acid ◽  
Synovial Fluid ◽  
Culture Conditions ◽  
Cytokine Secretion ◽  
Cationic Amino Acid Transporter ◽  
Cationic Amino Acid ◽  
The Relationship ◽  
Fibroblast Like Synoviocytes

Abstract Background: Abnormal proliferation of fibroblast-like synoviocytes (FLSs) in the synovial lining layer is the primary cause of synovial hyperplasia and joint destruction in rheumatoid arthritis (RA). Currently, the relationship between metabolic abnormalities and FLS proliferation is a new focus of investigation. However, little is known regarding the relationship between amino acid metabolism and RA. Methods: The concentrations of amino acids and cytokines in the synovial fluid of RA (n=9) and osteoarthritis (OA,n=9) were detected by LC-MS/MS and CBA assay, respectively. The mRNA and protein expression of CAT-1 were determined in FLSs isolated from RA and OA patients by real-time PCR and western blotting. MTT assay, cell cycle, apoptosis, invasion and cytokine secretion were determined in FLSs knocked down of CAT-1 using siRNA or treated with D-arginine under normoxic and hypoxic culture conditions. A mouse collagen-induced arthritis (CIA) model was applied to test the therapeutic potential of blocking the uptake of L-arginine in vivo.Results: L-arginine was upregulated in the synovial fluid of RA patients and was positively correlated with elevation of the cytokines IL-1β, IL-6 and IL-8. Further examination demonstrated that cationic amino acid transporter-1 (CAT-1) was the primary transporter for L-arginine and was overexpressed on RA FLSs compared to OA FLSs. Moreover, knockdown of CAT-1 using siRNA or inhibition of L-arginine uptake using D-arginine significantly suppressed L-arginine metabolism, cell proliferation, migration and cytokine secretion in RA FLSs under normoxic and hypoxic culture conditions in vitro but increased cell apoptosis in a dose-dependent manner. Meanwhile, in vivo assays revealed that an L-arginine-free diet or blocking the uptake of L-arginine using D-arginine suppressed arthritis progression in CIA mice. Conclusion: CAT-1 is upregulated and promotes FLS proliferation by taking up L-arginine, thereby promoting RA progression.

Modulation of thermogenic response to parenteral amino acid infusion in surgical stress

Nutrition ◽  
1996 ◽  
Vol 12 (1) ◽  
pp. 36-39 ◽  
Author(s):  
Toshimasa Tsujinaka ◽  
Masanori Sakaue ◽  
Shohei Iijima ◽  
Chikara Ebisui ◽  
Kazuomi Kan ◽  
...  
Keyword(s):  
Amino Acid ◽  
Surgical Stress ◽  
Acid Infusion ◽  
Amino Acid Infusion ◽  
Thermogenic Response
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