Amino acid metabolism and cell volume regulation in the little skate,Raja erinacea. II. Synthesis

1980 ◽  
Vol 212 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Patricia A. King ◽  
Chung-Ja Cha ◽  
Leon Goldstein
Keyword(s):  
Amino Acid ◽  
Cell Volume ◽  
Volume Regulation ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Cell Volume Regulation ◽  
Raja Erinacea

Correlation between osmoregulation and cell volume regulation

1987 ◽  
Vol 252 (4) ◽  
pp. R768-R773
Author(s):  
M. A. Lang
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Osmotic Pressure ◽  
Cell Volume ◽  
Free Amino Acids ◽  
Volume Regulation ◽  
Free Amino ◽  
Cell Volume Regulation

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.

TAURINE TRANSPORT CHARACTERISTICS OF THE EMBRYONIC SKATE (RAJA EGLANTERIA) HEART

1993 ◽  
Vol 182 (1) ◽  
pp. 291-295
Author(s):  
L. Goldstein ◽  
C. A. Luer ◽  
P. C. Blum
Keyword(s):  
Amino Acid ◽  
Cell Volume ◽  
Volume Regulation ◽  
Cell Volume Regulation ◽  
Extracellular Fluid ◽  
Beta Alanine ◽  
Hypotonic Stress ◽  
High Concentrations ◽  
Clearnose Skate ◽  
Raja Eglanteria

The hearts of elasmobranchs, like those of other vertebrates, accumulate high concentrations of the amino acid taurine (Boyd et al. 1977), which is used to maintain osmotic equilibrium with the extracellular fluid. We recently demonstrated that embryonic hearts of the clearnose skate (Raja eglanteria Bosc) were able to accumulate taurine equally as well as hearts of adult skates and, as in adults, the accumulation was the result of transport from extracellular taurine across the cell membrane against a steep concentration gradient (Goldstein et al. 1990). In adult skate hearts, the uptake of taurine is Na+-dependent and competitively inhibited by beta-alanine (Forster and Hannafin, 1980a), indicating that transport occurs by the beta-amino acid system found in many vertebrate hearts (Huxtable, 1992). During hypotonic stress, adult skate hearts release taurine and other amino acids. The Na+/taurine cotransport system permits the skate heart to maintain high concentrations of intracellular taurine, while the hypotonicity-activated taurine release aids in cell volume regulation following dilution of the extracellular fluid. The aims of the present study were to determine whether taurine uptake in the embryonic skate heart is Na+-dependent as in the adult and whether the skate heart has the capability of cell volume regulation (during hypotonic stress) before hatching.

scholarly journals Effects of changes in cell volume on the rates of glutamine and alanine release from rat skeletal muscle in vitro

1991 ◽  
Vol 276 (2) ◽  
pp. 559-561 ◽  
Author(s):  
M Parry-Billings ◽  
S J Bevan ◽  
E Opara ◽  
E A Newsholme
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Amino Acid ◽  
Cell Volume ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Rat Skeletal Muscle

The effect of changes in cell volume on the rates of release of glutamine and alanine from muscle and on the concentrations of these amino acids in muscle were investigated by using an isolated preparation of rat skeletal muscle incubated in the presence of hypo- and hyper-osmotic media. Changes in cell volume were associated with changes in the rates of release of glutamine and alanine from muscle: incubation in hypo-osmotic medium decreased the rates of release of glutamine and alanine, and incubation in hyperosmotic medium increased these rates. These changes were rapidly reversed by a change in osmoticity of the medium. Despite marked changes in cell volume, the concentrations of these amino acids in muscle were maintained. It is suggested that cell volume may play a role in the regulation of amino acid metabolism in skeletal muscle.

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