Changes in Plasma Amino Acids During the Oral Glucose Tolerance Test and the Effect of these Changes on Hepatic Encephalopathy

Abstract

Changes in amino acid concentrations in plasma during a 100 g oral glucose tolerance test were investigated in patients with liver cirrhosis and in healthy controls. In the controls, almost all amino acid concentrations reached a nadir about 3 hours after glucose loading, then returned to initial levels after 6 hours. Immunoreactive insulin levels reached a peak about 30 minutes aftef loading, then decreased gradually, reaching initial levels after 6 hours. In the controls, the decrease ratios/defined äs maximum decrease during the 3 hours after loading/initial concentration in plasma, were 0.607 and 0.554 for isoleucine (Ile) and leucine (Leu) respectively and 0.382 for valine (Val) which is significantly lower than for Ile or Leu. A similar tendency was recognized in patients with liver cirrhosis. The initial concentration of tyrosine (Tyr) and phenylalanine (Phe) in liver cirrhosis was significantly higher and their decrease ratios were significantly lower than in controls. Though no difference was observed between initial concentrations of tryptophan (Trp) in controls and liver cirrhosis patients, the decrease ratio of Trp in liver cirrhosis was lower (0.061) than that of controls (0.279) (p < 0.001).The value, t-Trp/BCAA + AAA, i.e. total Trp concentration (mmol/l)/concentration (mmol/1) of branched chain amino acids (BCAA, Ile + Leu + Val) plus aromatic amino acids (AAA, Tyr + Phe), which is known to correlate with the brain Tip concentration of rats (Fernstrom,

Personalized Metabolomics for Predicting Glucose Tolerance Changes in Sedentary Women After High-Intensity Interval Training

“…This is in agreement with previous metabolomic studies that have noted specific decreases in plasma amino acids after glucose ingestion reflecting reduced protein catabolism due to insulin action1929. Leu ( p = 1.84 E-18) had the most significant time-dependent decrease in plasma among all other polar metabolites, including Ile ( p = 2.18 E-10) and Val ( p = 4.90 E-7)2027. Also, Phe ( p = 2.87 E-12) and Met ( p = 3.08 E-12) were among the top three amino acids (after Leu) that decrease in plasma with post-prandial glucose.…”

“…Previous studies have shown that insulin levels typically peak around 30 min after glucose loading, whereas plasma amino acids do not return to baseline until after 6 h27. Proteolysis is a pathway that is inhibited with glucose loading, resulting in selective tissue uptake of (conditionally) essential amino acids for protein biosynthesis, notably branched-chain (Leu, Ile, Val) and aromatic amino acids (Phe, Trp, Tyr), as well as Met and Lys28.…”

Why Are Branched-Chain Amino Acids Increased in Starvation and Diabetes?

“…The importance of glycolysis for BCAA catabolism is clearly evidenced by the most significant decrease in BCAA levels of all amino acids during the oral glucose tolerance test or euglycemic insulin clamp [ 42 , 43 , 44 , 45 , 46 , 47 , 48 ].…”

Characteristic Profiles of Plasma Amino Acids before and after Glucose Loading in Patients with Acute Hepatitis compared with Chronic Liver Diseases

“…As insulin and glucagon are important hormones involved in the metabolism of amino acids, we investigated the relationship among these hormones, glucose and amino acids in plasma in liver diseases during oGrrio) 11) In this study, many significant correlations were observed among plasma Ala, Trp, Val, Lys, Glu, Tyr, His, FPG and IRG. Furthermore, we found a peculiar pattern of Ala level during OGTT only in acute hepatitis in acute stage.…”