Intestinal Absorption of Glycine and Glycyl-L-Proline in the Rat

1977 ◽  
Vol 52 (6) ◽  
pp. 607-614 ◽  
Author(s):  
R. C. Heading ◽  
H. P. Schedl ◽  
L. D. Stegink ◽  
D. L. Miller

1. Absorption of [3H]glycine and [14C]-glycyl-l-proline at concentrations between 0·5 and 4 mmol/l was studied by perfusion in vivo of rat jejunal and ileal segments. Absorption was defined as net removal of radioisotope from the perfusate. Radioactivity assays and amino acid analyses were performed on perfusates and on mucosal tissue samples obtained from the perfused segments. 2. At the concentrations studied, absorption rates of glycine and glycylproline were proportional to concentration. Ileal rates were approximately 60% of jejunal rates. Glycylproline absorption was slightly faster than glycine absorption and was associated with the appearance in the perfusate of free glycine and proline in the ratio approximately 3:1. Intraluminal hydrolysis was insufficient to account for the amounts of free amino acids found and glycylproline hydrolase activity at the brush border is known to be minimal. 3. Glycylproline absorption apparently occurred by transport of the intact peptide followed by its intracellular hydrolysis. However, more than one-third of absorbed glycine and one-eighth of absorbed proline returned to the lumen as free amino acid. This reflux of glycine and proline was not proportional to their concentrations in the mucosa.

1980 ◽  
Vol 239 (6) ◽  
pp. G493-G496 ◽  
Author(s):  
E. J. Feldman ◽  
M. I. Grossman

Using intragastric titration in dogs with gastric fistulas, dose-response studies were carried out with liver extract and with a mixture of amino acids that matched the free amino acids found in liver extract. All solutions were adjusted to pH 7.0 and osmolality to 290 mosmol x kg-1. Doses are expressed as the sum of the concentrations of all free amino acids. At each dose studied (free amino acid concentration: 2.8, 5.6, 11, 23, and 45 mM), acid secretion in response to the free amino acid mixture was not significantly different from that of liver extract. The peak response to both liver extract and the free amino acid mixture occurred with the 23-mM dose and represented about 60% of the maximal response to histamine. The serum concentrations of gastrin after liver extract and the amino acid mixture were not significantly different. It is concluded that in dogs with gastric fistula, gastric acid secretion and release of gastrin were not significantly different in response to liver extract and to a mixture of amino acids that simulated the free amino acid content of liver extract.


2021 ◽  
Vol 233 ◽  
pp. 02040
Author(s):  
Xuting Bai ◽  
Tao Li ◽  
Honglei Zhao ◽  
Xuepeng Li ◽  
Wenhui Zhu ◽  
...  

Protamex was selected to prepare the hydrolysate. E-tongue, free amino acid combined with soluble peptide analysis were used to detect the flavor changes of Aloididae aloidi during enzymolysis. Degree of proteolysis increased with the prolongation of enzymolysis time, and reached the maximum value at 8 hours. The content of soluble peptide of hydrolysate increased firstly and then decreased in the later process. The E-tongue could effectively distinguish the taste difference of hydrolysates at different enzymolysis time, and the hydrolysate presented strong bitterness and astringency during the whole enzymolysis. The total amount of free amino acids in the hydrolysate increased gradually, and some sweet, umami and bitter amino acids increased in varying degrees during the process of enzymolysis.


Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1637
Author(s):  
Quintino Reis de Araujo ◽  
Guilherme Amorim Homem de Abreu Loureiro ◽  
Cid Edson Mendonça Póvoas ◽  
Douglas Steinmacher ◽  
Stephane Sacramento de Almeida ◽  
...  

Free amino acids in cacao beans are important precursors to the aroma and flavor of chocolate. In this research, we used inferential and explanatory statistical techniques to verify the effect of different edaphic crop conditions on the free amino acid profile of PH-16 dry cacao beans. The decreasing order of free amino acids in PH-16 dry cacao beans is leucine, phenylalanine, glutamic acid, alanine, asparagine, tyrosine, gamma-aminobutyric acid, valine, isoleucine, glutamine, lysine, aspartic acid, serine, tryptophan, threonine, glycine. With the exception of lysine, no other free amino acid showed a significant difference between means of different edaphic conditions under the ANOVA F-test. The hydrophobic free amino acids provided the largest contribution to the explained variance with 58.01% of the first dimension of the principal component analysis. Glutamic acid stands out in the second dimension with 13.09%. Due to the stability of the biochemical profile of free amino acids in this clonal variety, it is recommended that cacao producers consider the genotype as the primary source of variation in the quality of cacao beans and ultimately the chocolate to be produced.


1969 ◽  
Vol 50 (2) ◽  
pp. 319-326
Author(s):  
R. R. HARRIS

1. Non-protein and protein nitrogen fractions of the isopod Sphaeroma rugicauda were measured in animals adapted to 100 and 2% sea water. 2. The non-protein nitrogen component was reduced in animals acclimatized to the lower salinity. 3. Free amino acids accounted for 88 and 74% respectively of the non-protein nitrogen in the two salinities. 4. In 2% sea water taurine, proline, glycine, alanine and glutamic acid showed the greatest decreases in concentration compared to the levels measured in animals adapted to 100% sea water. 5. The decrease in total free amino acids of animals acclimatized to 100% sea water and transferred to 2% sea water was measured. 6. The total free amino acid concentration is reduced to the 2% sea water level within 12 hr. after transfer. 7. Free amino acid, haemolymph sodium and total body sodium levels after transfer to 2% sea water were compared. 8. The asymmetry between the fall in haemolymph sodium concentration and the decrease in total body sodium under these conditions is thought to be due to a water shift from the haemolymph into the tissues. 9. It is suggested that the osmotic pressure of the cells falls at a slower rate than that of the haemolymph.


1987 ◽  
Vol 252 (4) ◽  
pp. R768-R773
Author(s):  
M. A. Lang

The euryhaline crab, Callinectes sapidus, behaves both as an osmoregulator when equilibrated in salines in the range of 800 mosM and below and an osmoconformer when equilibrated in salines above 800 mosM. There exists a close correlation between osmoregulation seen in the whole animal in vivo and cell volume regulation studied in vitro. Hyperregulation of the hemolymph osmotic pressure and cell volume regulation both occurred in salines at approximately 800 mosM and below. During long-term equilibration of the crabs to a wide range of saline environments, the total concentration of hemolymph amino acids plus taurine remained below 3 mM. During the first 6 h after an acute osmotic stress to the whole animal, the hemolymph osmotic pressure and Na activity gradually decreased, whereas the free amino acids remained below 3 mM. As the hemolymph osmotic pressure decreased below approximately 850 mosM, the amino acid level began to increase to 17-25 mM. This change was primarily due to increases in glycine, proline, taurine, and alanine. The likely source of the increase in hemolymph free amino acids in vivo is the free amino acid loss from muscle cells observed during cell volume regulation in vitro.


1956 ◽  
Vol 9 (4) ◽  
pp. 539 ◽  
Author(s):  
JV Possingham

The lovel and the qllHnj~itat,jve compositien of the free amino acid fraction of tomato plants grown in full nutrient and in cultures doficiollt ill zinc, copper, nlallganeso, iron. and molybdenum have beon cletormiuecl. 'I'he methods used in the investigation inelude the quantitative estimation of amino aeids by a technique involving paper chromatogl'l1phy, and the cultm'o of tomato plants in highly purified n utriollt solutions.


1981 ◽  
Vol 8 (2) ◽  
pp. 113-116 ◽  
Author(s):  
Harold E. Pattee ◽  
Clyde T. Young ◽  
Francis G. Giesbrecht

Abstract Peanuts from a commercial source were segregated into specific seed sizes and placed in storage conditions approximating commercial conditions to determine the amino acid changes taking place during storage within various size seeds. Concentrations of the isolated free amino acid fractions significantly decreased with seed size except for phenylalanine which significantly increased with seed size. Significant changes also occurred in the free amino acid fractions across storage periods up to nine months in duration. These results are the first to document a change in amino acids during the storage of peanuts.


1973 ◽  
Vol 59 (1) ◽  
pp. 57-63 ◽  
Author(s):  
W. DE LOECKER ◽  
M. L. STAS

SUMMARY Changes in the concentrations of free amino acids in intracellular fluids and blood plasma were measured in rats treated with cortisol. Increasing age raised the concentrations of free amino acids in plasma, while in liver, with the exception of glycine and alanine, decreased concentrations were observed. Cortisol treatment reduced free amino acid levels in plasma and liver which suggested a progressive catabolism of body proteins and increased protein synthesis in the liver. In skeletal muscle of control rats the free amino acid concentrations increased during the experimental period. Cortisol increased the concentration of certain amino acids and decreased that of others due to an increased protein turnover in muscle.


1993 ◽  
Vol 23 (4) ◽  
pp. 665-672 ◽  
Author(s):  
Christoph S. Vogel ◽  
Jeffrey O. Dawson

Changes in tissue nitrogen, phosphorus, and foliar free amino acids of four temperate woody deciduous plants (autumn olive (Elaeagnusumbellata Thunb.), black locust (Robiniapseudoacacia L.), American sycamore (Platanusoccidentalis L.), and honey locust (Gleditsiatriacanthos L.)) were determined during the autumns of 1987 and 1988 on two physically and nutritionally distinct sites in central Illinois, United States. The dinitrogen-fixing species, actinorhizal autumn olive (Frankia nodulated) and leguminous black locust (Rhizobium nodulated), resorbed a greater proportion of phosphorus than nitrogen from leaves prior to autumnal leaf abscission in comparison with the nonfixing American sycamore and honey locust. The net autumnal changes in nitrogen or phosphorus of each species did not differ with site in most cases. Free amino acid contents of leaves tended to decline as leaves senesced during the drier autumn of 1987; however, during the autumn of 1988 foliar free amino acid contents tended to increase as the season progressed, with abscised leaves having the greatest contents. Root bark seemed to be a major sink for phosphorus during autumn in the dinitrogen-fixing species, while all of the species investigated showed significant autumnal increases in twig-bark concentrations of nitrogen.


1973 ◽  
Vol 132 (3) ◽  
pp. 353-359 ◽  
Author(s):  
Isa K. Mushahwar ◽  
Roger E. Koeppe

Determination of the free amino acid and lactate content of testicular tissue in rat, guinea pig, rabbit, cat, gerbil, hamster, chicken and bullfrog indicates a substantial species variation. Insulin hypoglycaemia and ammonium acetate toxicity changes the concentration of several free amino acids of rat testes. 14C radioactivity from labelled acetate and ethanol is rapidly incorporated into some of the free amino acids of rat testes in vivo, whereas incorporation from [14C]glucose is relatively slow. These results have been compared with those obtained from similar studies with rat brain. In contrast to brain, there is no evidence for glutamate compartmentation in testes.


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