scholarly journals Amino acid metabolism in various fractions of rat-brain homogenates with special reference to the effect of ethanol

1967 ◽  
Vol 105 (1) ◽  
pp. 261-269 ◽  
Author(s):  
Hertta-Maija Häkkinen ◽  
E. Kulonen
Keyword(s):  
Amino Acid ◽  
Incubation Time ◽  
Soluble Protein ◽  
Protein Fraction ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Soluble Protein Fraction ◽  
Metabolic Difference ◽  
The Brain

1. The increase in brain γ-aminobutyrate, glutamate and aspartate and the decrease in brain glutamine that occur when ethanol is administered to rats in vivo could be reproduced by incubating brain homogenates from rats pretreated with ethanol. 2. For the demonstration of the effects of pretreatment with ethanol on the metabolism of γ-aminobutyrate and glutamine, the whole homogenate could be replaced by various supernatant preparations, and even by the soluble protein fraction, which was less active, however. The ‘postmitochondrial’ sediment could likewise mediate the effects of pretreatment with ethanol. 3. When the brain homogenates from control and ethanol-treated rats were allowed to ‘age’ at 2° for more than 7 days, the metabolic difference at incubation could no longer be demonstrated. The capacities of the homogenate from the control rats had changed to resemble those of ethanol-treated rats. 4. Data are given on the effects of the incubation time and of the concentration of homogenate.

scholarly journals Fungal Enzyme l-Lysine α-Oxidase Affects the Amino Acid Metabolism in the Brain and Decreases the Polyamine Level

2020 ◽  
Vol 13 (11) ◽  
pp. 398
Author(s):  
Elena V. Lukasheva ◽  
Marina G. Makletsova ◽  
Alexander N. Lukashev ◽  
Gulalek Babayeva ◽  
Anna Yu. Arinbasarova ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Tca Cycle ◽  
Polyamine Level ◽  
The Brain ◽  
Oxidative Species

The fungal glycoprotein l-lysine α-oxidase (LO) catalyzes the oxidative deamination of l-lysine (l-lys). LO may be internalized in the intestine and shows antitumor, antibacterial, and antiviral effects in vivo. The main mechanisms of its effects have been shown to be depletion of the essential amino acid l-lys and action of reactive oxidative species produced by the reaction. Here, we report that LO penetrates into the brain and is retained there for up to 48 h after intravenous injection, which might be explained by specific pharmacokinetics. LO actively intervenes in amino acid metabolism in the brain. The most significant impact of LO was towards amino acids, which are directly exposed to its action (l-lys, l-orn, l-arg). In addition, the enzyme significantly affected the redistribution of amino acids directly associated with the tricarboxylic acid (TCA) cycle (l-asp and l-glu). We discovered that the depletion of l-orn, the precursor of polyamines (PA), led to a significant and long-term decrease in the concentration of polyamines, which are responsible for regulation of many processes including cell proliferation. Thus, LO may be used to reduce levels of l-lys and PA in the brain.

Glucagon receptor signaling is not required for N-carbamoyl glutamate- and l-citrulline-induced ureagenesis in mice

2020 ◽  
Vol 318 (5) ◽  
pp. G912-G927
Author(s):  
Katrine D. Galsgaard ◽  
Jens Pedersen ◽  
Sasha A. S. Kjeldsen ◽  
Marie Winther-Sørensen ◽  
Elena Stojanovska ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Urea Cycle ◽  
Receptor Signaling ◽  
Glucagon Receptor ◽  
Acetylglutamate Synthase

Hepatic ureagenesis is essential in amino acid metabolism and is importantly regulated by glucagon, but the exact mechanism is unclear. With the aim to identify the steps whereby glucagon both acutely and chronically regulates ureagenesis, we here show, contrary to our hypothesis, that glucagon receptor-mediated activation of ureagenesis is not required when N-acetylglutamate synthase activity and/or N-acetylglutamate levels are sufficient to activate the first step of the urea cycle in vivo.

Effect of age and temperature on amino acid composition and the content of different protein types of juvenile Atlantic cod (Gadus morhua) otoliths

2004 ◽  
Vol 61 (6) ◽  
pp. 1012-1020 ◽  
Author(s):  
K Hüssy ◽  
H Mosegaard ◽  
F Jessen
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Soluble Protein ◽  
Protein Fraction ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Water Soluble ◽  
Soluble Protein Fraction ◽  
Water Soluble Protein

The purpose of this study was to analyse the amino acid composition of otolith matrix protein, estimate the proportion of the water-soluble protein fraction, and analyse the effect of matrix composition on otolith visual appearance. Juvenile Atlantic cod (Gadus morhua) were reared under constant temperature and feeding conditions and sampled at the beginning and the end of the experiment. The amino acid composition was dominated by asparagine, glutamic acid, leucine, serine, and proline. A change in amino acid composition was observed with increasing temperature and time, caused by changing proportions of the water-soluble and -insoluble protein fractions. Feeding level had no effect. The relative content of water-soluble protein was linearly related to fish dry weight and temperature. Otolith opacity, defined as the percentage of incident light absorbed by an otolith section, did not differ significantly between experimental treatments. The soluble protein fraction had a positive, albeit insignificant, correlation with opacity. Using opacity and otolith volume, deposited total otolith protein content was estimated with an R2 of 0.91, where otolith volume alone explained 83% of the observed variation.

Renal serine production in vivo: effects of dietary manipulation of serine status

1989 ◽  
Vol 67 (9) ◽  
pp. 1058-1061 ◽  
Author(s):  
John T. Brosnan ◽  
Beatrice Hall
Keyword(s):  
Amino Acids ◽  
Blood Flow ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Dietary Manipulation ◽  
In Vivo Effects ◽  
Crystalline Amino Acids ◽  
Arteriovenous Difference

Renal serine production in rats was quantitated by simultaneously measuring renal blood flow and the renal arteriovenous difference for this amino acid. The rate of synthesis was 0.24 ± 0.02 μmol∙min−1∙100 g−1 in rats fed a diet containing 12% casein. This rate was not altered by the inclusion of an additional 1% serine in the diet for 7 days or by acute infusion of serine, although both protocols increased blood serine by 50%. When rats were fed a diet in which protein was entirely replaced by crystalline amino acids the rate of renal serine production was also 0.25 ±0.05 μmol∙min−1∙100 g−1. Omission of serine or both serine and glycine from this diet did not alter the rate of renal serine synthesis. Renal serine production does not respond to the serine content of the diet.Key words: serine, glycine, kidney, amino acid metabolism.

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