CHANGES OF FREE AMINO ACIDS IN PANCREATIC β-CELLS AFTER STARVATION AND SUBSTRATE DEPRIVATION

1974 ◽  
Vol 75 (1) ◽  
pp. 105-118 ◽  
Author(s):  
Erik Gylfe
Keyword(s):  
Amino Acid ◽  
Aspartic Acid ◽  
Free Amino ◽  
Aminobutyric Acid ◽  
Β Cell ◽  
Freeze Dried ◽  
Amino Acid Efflux ◽  
Substrate Deprivation ◽  
Amino Acid Concentrations ◽  
Very High

ABSTRACT A procedure for free amino acid measurements in β-cell-rich pancreatic islets from obese-hyperglycaemic mice involving reaction with 3H-dansyl chloride and subsequent chromatographic separation was studied. A characteristic feature of the islets was the presence of γ-aminobutyric acid and of very high taurine concentrations. Islets dissected from fresh pancreas contained more leucine and valine than specimens obtained from freeze-dried pancreatic sections. When micro-dissected islets were incubated in substrate-free medium the concentrations of leucine and valine remained high, whereas aspartic acid decreased. Perifusion of islets with the same type of medium, however, depressed the concentrations of glycine, leucine, lysine, phenylalanine and valine. Starvation increased the β-cell concentrations of γ-aminobutyric acid and leucine and reduced those of aspartic acid and glutamic acid. The possibilities that the amino acid concentrations are influenced by amino acid efflux or the uptake of secreted insulin in combination with protein catabolism are discussed.

Incorporation of carbon atoms from glucose into free amino acids in brain under normal and altered conditions

1970 ◽  
Vol 48 (3) ◽  
pp. 228-235 ◽  
Author(s):  
Y. Yoshino ◽  
K. A. C. Elliott
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Acid Level ◽  
Specific Activity ◽  
Specific Radioactivity ◽  
Aminobutyric Acid ◽  
Aminooxyacetic Acid

The time course of entry of radioactive carbon from intravenously administered [U-14C]-glucose into free amino acids in the brains of rats has been studied using an automatic amino acid analyzer coupled through a flow cell with a scintillation counter. Radioactivity appeared rapidly in alanine, aspartic acid, glutamic acid, glutamine, and γ-aminobutyric acid as previously shown, and in an unknown ninhydrin-positive substance present in very small amount. Urea, serine, and glycine became slightly radioactive. Four hours after giving the radioactive glucose, the specific activity in all soluble substances was low. In pentobarbital anesthesia, specific radioactivity was increased in alanine and decreased in γ-aminobutyric acid, aspartic and glutamic acids, and glutamine. A high proportion of radioactivity remained in glucose. Under hypoxia, alanine increased in amount but decreased in specific activity, and the specific activities of the other strongly labelled amino acids decreased. The proportion of the total radioactivity found in glucose and lactate increased. During picrotoxin and pentylenetetrazol convulsions, changes occurred which were similar to those under hypoxia. After aminooxyacetic acid administration, the well-known great increase in γ-aminobutyric acid level was found to be accompanied by a decrease in glutamate and also in aspartic acid and alanine, indicating inhibition of the three transaminases concerned. The previously observed brief rapid postmortem increase in the amount of γ-aminobutyric acid was confirmed; alanine also increased briefly but no other amino acid did so. The increased γ-aminobutyric acid had the same specific radioactivity as the original but the extra alanine was less radioactive than the original. When the γ-aminobutyric acid level had been increased by administration of aminooxyacetic acid, the rapid postmortem increase did not occur.

Free Amino Acid Concentrations in Leaves of Sodium-Deficient C4 Plants

1986 ◽  
Vol 13 (3) ◽  
pp. 343 ◽  
Author(s):  
CPL Grof ◽  
M Johnston ◽  
PF Brownell
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Free Amino ◽  
Aminobutyric Acid ◽  
Amaranthus Tricolor ◽  
Mature Leaves ◽  
C4 Species ◽  
Chloris Gayana ◽  
Amino Acid Concentrations

Consistent changes in the free amino acid concentrations in response to sodium nutrition were observed in mature leaves of the C4 species Amaranthus tricolor and Chloris gayana. The amino acids alanine, γ-aminobutyric acid and glycine were present in greater and aspartate and arginine in lower concentrations in mature leaves of sodium-deficient than in normal plants of both species.

Free amino acid concentrations in needles of Norway spruce and Scots pine trees on different sites in areas with two levels of nitrogen deposition

1990 ◽  
Vol 20 (8) ◽  
pp. 1132-1136 ◽  
Author(s):  
Ann-Britt Edfast ◽  
Torgny Näsholm ◽  
Anders Ericsson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Nitrogen Deposition ◽  
Free Amino Acids ◽  
Free Amino ◽  
Aminobutyric Acid ◽  
Site Quality ◽  
Southern Sweden ◽  
Amino Acid Concentrations

The effects of nitrogen deposition and site quality on amino acid concentrations in needles of Piceaabies (L.) Karst. and Pinussylvestris L. trees were studied in two areas that represent different levels of nitrogen deposition: one area in southern Sweden and one area in northern Sweden receive, respectively, approximately 20–30 and 3 kg•ha−1•year−1 of nitrogen. On each area three site quality classes were chosen for each tree species. The site classes were chosen to represent poor, medium, and good sites typical for each area. Free amino acids in the needles were analyzed as 9-fluorenylmethyl formate derivatives by high-performance liquid chromatography. The total nitrogen was determined with a CHN elemental analyzer, and other mineral nutrients were determined with an inductively coupled plasma analyzer. Arginine, glutamic acid, glutamine, γ-aminobutyric acid, and aspartic acid were the quantitatively dominating amino acids in the needles of both species from all sites in both northern and southern Sweden. These amino acids represented 50–80% of the total concentration of free amino acids in the needles. The concentration of arginine in the needles of both spruce and pine increased with decreasing site index and showed high variations between individual trees. For both species, the highest concentrations of arginine were found in the southern area, which had the highest deposition of nitrogen. Concentrations of glutamic acid, glutamine, and γ-aminobutyric acid in the needles of both species showed significant differences between some of the sites on both areas, but these differences showed no general pattern that correlated with the site indexes. In relation to nitrogen, low concentrations of phosphorus and potassium were found in needles from the poorest spruce sites in both areas compared with corresponding values for the good spruce sites. The results are discussed in relation to nitrogen deposition and mineral nutrient imbalance.

Free amino acid concentrations in cerebral cortex of guinea pigs with epileptogenic lesions

1962 ◽  
Vol 5 (6) ◽  
pp. 525-532 ◽  
Author(s):  
Yo Aelony ◽  
John Logothetis ◽  
Bruce Bart ◽  
Frank Morrell ◽  
Magdaline Bovis
Keyword(s):  
Cerebral Cortex ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Guinea Pigs ◽  
Free Amino ◽  
Amino Acid Concentrations

scholarly journals Use of UPLC-ESI-MS/MS to quantitate free amino acid concentrations in micro-samples of mammalian milk

SpringerPlus ◽  
2013 ◽  
Vol 2 (1) ◽  
pp. 622 ◽  
Author(s):  
Véronique Roucher ◽  
Emmanuelle Desnots ◽  
Charlotte Naël ◽  
Aurore Agnoux ◽  
Marie-Cécile Alexandre-Gouabau ◽  
...  
Keyword(s):  
Amino Acid ◽  
Free Amino Acid ◽  
Free Amino ◽  
Esi Ms ◽  
Amino Acid Concentrations

Volume-sensitive amino acid efflux from a pancreatic β-cell line

2000 ◽  
Vol 162 (1-2) ◽  
pp. 201-208 ◽  
Author(s):  
A.C.G. Grant ◽  
J. Thomson ◽  
V.A. Zammit ◽  
D.B. Shennan
Keyword(s):  
Amino Acid ◽  
Cell Line ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Amino Acid Efflux
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