In vivo protein synthesis in different tissues and the whole body of rainbow trout (Salmo gairdnerii R.). Influence of environmental temperature

1985 ◽  
Vol 82 (1) ◽  
pp. 179-187 ◽  
Author(s):  
B Fauconneau ◽  
M Arnal
Author(s):  
Jorn Trommelen ◽  
Andrew M. Holwerda ◽  
Philippe J. M. Pinckaers ◽  
Luc J. C. van Loon

All human tissues are in a constant state of remodelling, regulated by the balance between tissue protein synthesis and breakdown rates. It has been well-established that protein ingestion stimulates skeletal muscle and whole-body protein synthesis. Stable isotope-labelled amino acid methodologies are commonly applied to assess the various aspects of protein metabolism in vivo in human subjects. However, to achieve a more comprehensive assessment of post-prandial protein handling in vivo in human subjects, intravenous stable isotope-labelled amino acid infusions can be combined with the ingestion of intrinsically labelled protein and the collection of blood and muscle tissue samples. The combined application of ingesting intrinsically labelled protein with continuous intravenous stable isotope-labelled amino acid infusion allows the simultaneous assessment of protein digestion and amino acid absorption kinetics (e.g. release of dietary protein-derived amino acids into the circulation), whole-body protein metabolism (whole-body protein synthesis, breakdown and oxidation rates and net protein balance) and skeletal muscle metabolism (muscle protein fractional synthesis rates and dietary protein-derived amino acid incorporation into muscle protein). The purpose of this review is to provide an overview of the various aspects of post-prandial protein handling and metabolism with a focus on insights obtained from studies that have applied intrinsically labelled protein under a variety of conditions in different populations.


1988 ◽  
Vol 254 (6) ◽  
pp. R891-R896 ◽  
Author(s):  
F. P. Lafeber ◽  
G. Flik ◽  
S. E. Wendelaar Bonga ◽  
S. F. Perry

Bidirectional whole body flux and branchial Ca2+ influx were measured in freshwater rainbow trout. Intra-arterial injections of homogenates of Stannius corpuscles (CS) as well as of a 54-kDa isolated product (hypocalcin) exerted an inhibitory effect on whole body Ca2+ influx, but did not effect Ca2+ efflux. Hypocalcin was more effective in reducing Ca2+ influx in trout acclimated to low-calcium freshwater than in fish from normal-calcium water. We conclude that the isolated product (hypocalcin) represents the hypocalcemic principle of the CS. Similar doses of hypocalcin caused quantitatively similar decreases in Ca2+ influx in vivo and in the isolated perfused head preparation. This indicates that the gills form the principle target for hypocalcin in trout. The branchial transepithelial potential did not change during hormone treatments. Possible mechanisms of hypocalcin action are suggested.


2001 ◽  
Vol 20 (2) ◽  
pp. 181-182 ◽  
Author(s):  
A. JANUSZKIEWICZ ◽  
P. ESSÉN ◽  
M.A. McNURLAN ◽  
O. RINGDÉN ◽  
P.J. GARLICK ◽  
...  

1985 ◽  
Vol 226 (1) ◽  
pp. 37-42 ◽  
Author(s):  
J J Pomposelli ◽  
J D Palombo ◽  
K J Hamawy ◽  
B R Bistrian ◽  
G L Blackburn ◽  
...  

Previous studies have reported that use of a flooding dose of radiolabelled amino acid is a more precise technique than the constant infusion of tracer quantities for determining rates of protein synthesis in rapidly turning-over tissues in the rat. However, there has been little direct investigation comparing different methods under comparable conditions. Initially, 12 healthy male Sprague-Dawley rats, weighing approx. 100 g, were randomized to receive either a bolus intravenous injection of 100 mumol of L-leucine (containing 30 microCi of [1-14C]leucine)/100 g body wt., or a continuous 2 h tracer infusion of [14C]leucine. In the second phase of the experiment, 12 additional rats were intravenously injected with 1 × 10(8) colony-forming units of Pseudomonas aeruginosa and 16 h later randomized to receive one of two infusions described above. Total protein synthesis as well as fractional synthesis rates were determined in liver, rectus muscle and whole body. Synthesis rates measured in liver, muscle and whole body were significantly higher in bacteraemic rats than in healthy rats. The flooding-dose methodology gave significantly higher estimates of protein synthesis in the liver, skeletal muscle and whole body than did the continuous-infusion method using direct measurement of the acid-soluble fraction from the respective tissue. Indirect estimates of whole-body protein synthesis based on plasma enrichments and stochastic modelling gave the lowest values.


1988 ◽  
Vol 91 (4) ◽  
pp. 765-768 ◽  
Author(s):  
Yosuke Aoyagi ◽  
Iwao Tasaki ◽  
Jun-ichi Okumura ◽  
Tatsuo Muramatsu

1984 ◽  
Vol 36 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Suzanne M. Harley ◽  
Harry Beevers

1991 ◽  
Vol 261 (1) ◽  
pp. R106-R116
Author(s):  
N. W. Istfan ◽  
P. R. Ling ◽  
G. L. Blackburn ◽  
B. R. Bistrian

To evaluate the accuracy of in vivo estimates of protein synthesis and breakdown, measurements of plasma and tissue leucine kinetics were made in rat tumor tissues at different conditions of growth by use of constant intravenous infusion of [14C]leucine. These measurements were made in Yoshida sarcoma tumors on days 10 and 13 after implantation, with and without tumor necrosis factor (TNF) infusion and on day 10 in Walker-256 carcinosarcoma. Expressed as micromoles of leucine per gram tissue, tumor protein breakdown increased (P less than 0.01) from 0.32 +/- 0.02 to 0.52 +/- 0.09 (SE) mumol/h, with progress of the Yoshida sarcoma tumor between days 10 and 13 after implantation. Similarly, TNF increased tumor proteolysis on day 10 (0.43 +/- 0.03 mumol.h-1.g-1, P less than 0.05 vs. day 10 control) but not on day 13 after implantation of the Yoshida tumor. Estimates of growth derived from the difference between protein synthesis and breakdown rates were not statistically different from those based on actual tumor volume changes in both tumor models. However, estimates of “whole body” protein metabolism (plasma leucine flux) were not affected either by tumor aging or by treatment with TNF. This study shows that in vivo estimates of tissue protein metabolism based on our [14C]leucine constant infusion model closely reflect the growth characteristic of that tissue. A cytotoxic perfusion-independent effect for intravenous TNF on growing tumor tissue is demonstrable as increased protein breakdown. Furthermore, the commonly used concept of whole body protein metabolism, derived solely from tracer dilution in plasma, is an oversimplification.


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