Adult Trichostrongylus colubriformis infection did not affect protein synthesis rate in whole-body, intestinal, hepatic and skeletal muscle tissues of lambs fed fresh Lucerne (Medicago sativa)

2007 ◽  
Vol 87 (3) ◽  
pp. 315-325 ◽  
Author(s):  
E. N. Bermingham ◽  
W. C. McNabb ◽  
I. A. Sutherland ◽  
B. R. Sinclair ◽  
B. P. Treloar ◽  
...  

The effects of an established Trichostrongylus colubriformis infection on the whole-body and fractional protein synthesis rates in the small intestine, liver, lymphoid tissues, skeletal muscle and skin were determined in lambs fed fresh Lucerne (Medicago sativa; 800 g DM d-1) on day 48 post-infection. Lambs were dosed with 6000 L3 T. colubriformis larvae for 6 d (n = 5) or kept as parasite-free controls (n = 6). On day 45, the lambs received a bolus injection of deuterated water to measure the size of the whole-body water pool. On day 48, the lambs were continuously infused with [3, 4-3H]-valine into the jugular vein and [1-13C]-valine in the abomasum for 8 h. During the infusion, mesenteric artery blood and terminal tissue samples were collected for measuring the isotopic activity of plasma water, plasma valine, intra cellular valine and protein-bound valine. Intestinal worm numbers on day 48 were higher (P < 0.001) in the infected lambs, however, there was no effect (P > 0.10) of parasitic infection on feed intake, liveweight gain, whole-body protein synthesis and fractional protein synthesis of most tissues. Key words: Parasite infection, protein synthesis, lambs


1992 ◽  
Vol 132 (3) ◽  
pp. 369-375 ◽  
Author(s):  
P. C. Bates ◽  
R. Aston ◽  
A. T. Holder

ABSTRACT Monoclonal antibody (MAb) to GH has been shown to increase the anabolic response induced by the hormone in individual tissues of dwarf mice. Dwarf mice were treated with GH at a low and a high dose (2·5 and 50 mU/day respectively), with and without complexing to an MAb. Treatment was for 7 and 14 days, at which times protein synthesis rates in skeletal muscle, liver and heart were determined from incorporation of labelled phenylalanine following injection of a flooding dose. The MAb potentiated the actions of GH and produced increases in the rates of protein synthesis in each of the tissues to a significantly greater extent than did GH alone. The increase in protein synthesis rate induced by MAb appears to be mechanistically distinct from that observed by increasing the dose of GH. In skeletal muscle and liver there was a dose–response to the GH alone in terms of the RNA concentration, i.e. the capacity for protein synthesis, whereas in each tissue examined the MAb caused very little further response in the RNA concentration. The MAb-induced enhancement of protein synthesis rate was almost entirely due to an increase in the RNA activity, i.e. the efficiency of the synthesizing system. Complexing GH to a particular MAb, or to antisera of restricted epitope specificity, has previously been shown to enhance the in-vivo effects of GH on whole body protein content; the mechanism for this enhancement has not been adequately determined. The present results suggest that the mechanism of MAb enhancement of GH activity is unlikely to be through prolonging GH action by increasing its serum half-life, but may be through effects on GH-receptor response, possibly through targeting of the GH to a particular receptor sub-type or through inhibition of internalization of the GH-receptor complex. Journal of Endocrinology (1992) 132, 369–375



1988 ◽  
Vol 254 (2) ◽  
pp. E208-E213 ◽  
Author(s):  
K. S. Nair ◽  
D. Halliday ◽  
R. C. Griggs

Fractional mixed skeletal muscle protein synthesis (FMPS) was estimated in 10 postabsorptive healthy men by determining the increment in the abundance of [13C]-leucine in quadriceps muscle protein during an intravenous infusion of L-[1-13C]leucine. FMPS in our subjects was 0.046 +/- 0.003%/h. Whole-body muscle protein synthesis (MPS) was calculated based on the estimation of muscle mass from creatinine excretion and compared with whole-body protein synthesis (WBPS) calculated from the nonoxidative portion of leucine flux. A significant correlation (r2 = 0.73, P less than 0.05) was found between MPS (44.7 +/- 3.4 mg.kg-1.h-1) and WBPS (167.8 +/- 8.5 mg.kg-1.h-1). The contribution of MPS to WBPS was 27 +/- 1%, which is comparable to the reports in other species. Morphometric analyses of adjacent muscle samples in eight subjects demonstrated that the biopsy specimens consisted of 86.5 +/- 2% muscular as opposed to other tissues. Because fiber type composition varies between biopsies, we examined the relationship between proportions of each fiber type and FMPS. Variation in the composition of biopsies and in fiber-type proportion did not affect the estimation of muscle protein synthesis rate. We conclude that stable isotope techniques using serial needle biopsies permit the direct measurement of FMPS in humans and that this estimation is correlated with an indirect estimation of WBPS.



1994 ◽  
Vol 86 (6) ◽  
pp. 663-669 ◽  
Author(s):  
D. Breuille ◽  
F. Rose ◽  
M. Arnal ◽  
C. Melin ◽  
C. Obled

1. Protein synthesis rate was measured in the liver, muscle, intestine and whole body of septic rats and pair-fed controls by administration of a large dose of l-[U14C]valine. Sepsis was induced by intravenous injection of live bacteria, and protein synthesis measurements were carried out 48 h later. 2. Septic rats exhibited a reduction in food intake to between 10 and 50% of the normal level on the 2 days after infection. Animals lost body weight and the relative organ weight was increased in liver, unchanged in intestine and decreased in skeletal muscle. 3. The fractional protein synthesis rate of the whole body excluding liver was increased by 19% in septic rats in comparison with pair-fed controls, but the absolute protein synthesis rate was similar in the two groups because of the low protein content of the infected group. 4. The fractional protein synthesis was increased in whole intestine and liver but was decreased in skeletal muscle. In muscle and liver, the difference between infected and pair-fed animals was more pronounced for the absolute than for the fractional protein synthesis rate. In intestine, the fractional protein synthesis rate was similarly increased in whole intestine and the muscular layer of ileum. This suggests different regulation of protein synthesis in skeletal and smooth muscles. 5. The present investigation shows a complete redistribution of protein synthesis in sepsis. Liver represents about a third of the whole-body protein synthesis instead of 15% and becomes predominant over synthesis of muscle.



1993 ◽  
Vol 264 (5) ◽  
pp. E824-E828 ◽  
Author(s):  
T. P. Stein ◽  
M. J. Leskiw ◽  
M. D. Schluter

Nitrogen balance and the whole body protein synthesis rate were measured before, during, and after a 9.5-day spaceflight mission on the space shuttle Columbia. Protein synthesis was measured by the single-pulse [15N]glycine method. Determinations were made 56, 26, and 18 days preflight, on flight days 2 and 8, and on days 0, 6, 14, and 45 postflight. We conclude that nitrogen balance was decreased during spaceflight. The decrease in nitrogen balance was greatest on the 1st day when food intake was reduced and again toward the end of the mission. An approximately 30% increase in protein synthesis above the preflight baseline was found for flight day 8 for all 6 subjects (P < 0.05), indicating that the astronauts showed a stress response to spaceflight.



1998 ◽  
Vol 275 (4) ◽  
pp. E577-E583 ◽  
Author(s):  
Kevin E. Yarasheski ◽  
Jeffrey J. Zachwieja ◽  
Jennifer Gischler ◽  
Jan Crowley ◽  
Mary M. Horgan ◽  
...  

Muscle protein wasting occurs in human immunodeficiency virus (HIV)-infected individuals and is often the initial indication of acquired immunodeficiency syndrome (AIDS). Little is known about the alterations in muscle protein metabolism that occur with HIV infection. Nine subjects with AIDS wasting (CD4 < 200/mm3), chronic stable opportunistic infections (OI), and ≥10% weight loss, fourteen HIV-infected men and one woman (CD4 > 200/mm3) without wasting or OI (asymptomatic), and six HIV-seronegative lean men (control) received a constant intravenous infusion of [1-13C]leucine (Leu) and [2-15N]glutamine (Gln). Plasma Leu and Gln rate of appearance (Ra), whole body Leu turnover, disposal and oxidation rates, and [13C]Leu incorporation rate into mixed muscle protein were assessed. Total body muscle mass/fat-free mass was greater in controls (53%) than in AIDS wasting (43%; P = 0.04). Fasting whole body proteolysis and synthesis rates were increased above control in the HIV+ asymptomatic group and in the AIDS-wasting group ( P = 0.009). Whole body Leu oxidation rate was greater in the HIV+ asymptomatic group than in the control and AIDS-wasting groups ( P < 0.05). Fasting mixed muscle protein synthesis rate was increased in the asymptomatic subjects (0.048%/h; P = 0.01) but was similar in AIDS-wasting and control subjects (0.035 vs. 0.037%/h). Plasma Gln Rawas increased in AIDS-wasting subjects but was similar in control and HIV+ asymptomatic subjects ( P < 0.001). These findings suggest that AIDS wasting results from 1) a preferential reduction in muscle protein, 2) a failure to sustain an elevated rate of mixed muscle protein synthesis while whole body protein synthesis is increased, and 3) a significant increase in Gln release into the circulation, probably from muscle. Several interesting explanations for the increased Gln Rain AIDS wasting exist.



2013 ◽  
Vol 304 (3) ◽  
pp. G300-G310 ◽  
Author(s):  
Patrycja Puiman ◽  
Barbara Stoll ◽  
Lars Mølbak ◽  
Adrianus de Bruijn ◽  
Henk Schierbeek ◽  
...  

We examined whether changes in the gut microbiota induced by clinically relevant interventions would impact the bioavailability of dietary amino acids in neonates. We tested the hypothesis that modulation of the gut microbiota in neonatal pigs receiving no treatment (control), intravenously administered antibiotics, or probiotics affects whole body nitrogen and amino acid turnover. We quantified whole body urea kinetics, threonine fluxes, and threonine disposal into protein, oxidation, and tissue protein synthesis with stable isotope techniques. Compared with controls, antibiotics reduced the number and diversity of bacterial species in the distal small intestine (SI) and colon. Antibiotics decreased plasma urea concentrations via decreased urea synthesis. Antibiotics elevated threonine plasma concentrations and turnover, as well as whole body protein synthesis and proteolysis. Antibiotics decreased protein synthesis rate in the proximal SI and liver but did not affect the distal SI, colon, or muscle. Probiotics induced a bifidogenic microbiota and decreased plasma urea concentrations but did not affect whole body threonine or protein metabolism. Probiotics decreased protein synthesis in the proximal SI but not in other tissues. In conclusion, modulation of the gut microbiota by antibiotics and probiotics reduced hepatic ureagenesis and intestinal protein synthesis, but neither altered whole body net threonine balance. These findings suggest that changes in amino acid and nitrogen metabolism resulting from antibiotic- or probiotic-induced shifts in the microbiota are localized to the gut and liver and have limited impact on whole body growth and anabolism in neonatal piglets.



1991 ◽  
Vol 66 (3) ◽  
pp. 423-435 ◽  
Author(s):  
N. O. Cortamira ◽  
B. Seve ◽  
Y. Lebreton ◽  
P. Ganier

Two experiments were carried out with piglets, 3–5 kg live weight, to evaluate the effects of feeding a tryptophan (TRP)-deficient diet for 2 weeks on protein synthesis rates measured in vivo 2 h after a meal. In the first experiment on twenty piglets fed on 250 g protein/kg diets, TRP deficiency (0.77 g/16 g nitrogen) as compared with adequacy (1.17 g/16 g N) significantly decreased feed intake, growth performance and fractional protein synthesis rates (FSR), without variation of RNA in longissimus dorsi (LD) and with parallel increases in RNA in semitendinosus (ST) muscle and liver. In the second experiment thirty-two piglets were tube-fed deficient and adequate diets at the two feeding levels (LF) previously achieved. Both TRP and LF significantly increased growth performance and FSR, but not RNA, in LD and ST muscle, with a trend to a synergy between the two factors (TRP x LF interaction). In another muscle, trapezius (TR), the same interaction was only apparent in RNA content. Among the three muscles it was in LD that FSR was the most responsive to dietary TRP (significant muscle x TRP interaction). In the liver the TRP x LF interaction on FSR and not RNA was the major significant effect, indicating that higher TRP and higher LF were both required to get the maximum protein synthesis rate. At 30 min after a meal the same significant interaction effect was shown on plasma glucose, whilst the higher LF increased plasma insulin with both diets. After a further 30 min the appearance of a similar significant effect of the TRP x LF interaction on plasma insulin resulted from its abatement when the deficient diet had been fed at high LF. These results suggest that dietary TRP deficiency decreased muscle and liver protein synthesis rates in relation to a decrease in the post-prandial release of insulin following a decreased rate of nutrient absorption.



1988 ◽  
Vol 60 (1) ◽  
pp. 77-84 ◽  
Author(s):  
D. Attaix ◽  
E. Aurousseau ◽  
A. Manghebati ◽  
M. Arnal

1. Protein fractional synthesis rate (FSR) was measured in some major tissues and in the whole body of six 1-week-old sucking lambs by a large injection of L-[3H]valine.2. Upper estimates of tissue protein FSR (%/d), assuming that the tissue-homogenate free-valine specific radioactivity defined that of valyl tRNA, were 115.0 in liver, 24.1 in skin, 22.9 in the white M. tensor fasciae latae, 21.6 in the red M. diaphragma and 19–6 in the remainder (exsanguinated whole body without liver and gastrointestinal tract) of lambs.3. Absolute synthesis rates (ASR) of tissue protein were 17, 19 and 42 g/d in the liver, skin and skeletal muscle respectively, and 112 g/d in the remainder. The ASR of whole-body protein, derived from the tissue values, was 146 g/d, i.e. 33 g/d per kg body-weight. The calculated whole-body protein FSR was 23.9 %/d.4. The relative percentage contribution of liver, skin and skeletal muscle to whole-body protein synthesis was 11.7, 13.1, and 29.0.5. We concluded that tissue protein FSR in lambs were in exactly the same decreasing order, from visceral tissues to skeletal muscles, as observed in rats. The ovine FSR estimates and the partitioning of protein synthesis between tissues were in the same range as values recently obtained by flooding-dose experiments in immature rats, piglets, and even in chicks. These findings suggest that inter-species differences are rather limited.



1992 ◽  
Vol 262 (3) ◽  
pp. E261-E267 ◽  
Author(s):  
K. E. Yarasheski ◽  
J. A. Campbell ◽  
K. Smith ◽  
M. J. Rennie ◽  
J. O. Holloszy ◽  
...  

The purpose of this study was to determine whether growth hormone (GH) administration enhances the muscle anabolism associated with heavy-resistance exercise. Sixteen men (21-34 yr) were assigned randomly to a resistance training plus GH group (n = 7) or to a resistance training plus placebo group (n = 9). For 12 wk, both groups trained all major muscle groups in an identical fashion while receiving 40 micrograms recombinant human GH.kg-1.day-1 or placebo. Fat-free mass (FFM) and total body water increased (P less than 0.05) in both groups but more (P less than 0.01) in the GH recipients. Whole body protein synthesis rate increased more (P less than 0.03), and whole body protein balance was greater (P = 0.01) in the GH-treated group, but quadriceps muscle protein synthesis rate, torso and limb circumferences, and muscle strength did not increase more in the GH-treated group. In the young men studied, resistance exercise with or without GH resulted in similar increments in muscle size, strength, and muscle protein synthesis, indicating that 1) the larger increase in FFM with GH treatment was probably due to an increase in lean tissue other than skeletal muscle and 2) resistance training supplemented with GH did not further enhance muscle anabolism and function.



1997 ◽  
Vol 273 (5) ◽  
pp. E898-E902 ◽  
Author(s):  
Odile Mansoor ◽  
Marc Cayol ◽  
Pierre Gachon ◽  
Yves Boirie ◽  
Pierre Schoeffler ◽  
...  

The effect of trauma on protein metabolism was investigated in the whole body, muscle, and liver in severely head-injured patients presenting an acute inflammatory response by comparison to fed control subjects receiving a similar diet. Nonoxidative leucine disposal (an index of whole body protein synthesis) and muscle, albumin, and fibrinogen synthesis were determined by means of a primed, continuous infusion ofl-[1-13C]leucine. Nonoxidative leucine disposal increased by 28% in the patients ( P < 0.02). Fractional muscle protein synthesis rate decreased by 50% ( P < 0.01) after injury. Fractional and absolute fribrinogen synthesis rates were multiplied by two and nine, respectively, after injury ( P< 0.001). Albumin levels were lower in patients (25.2 ± 1.2 g/l, means ± SE) than in controls (33.7 ± 1.2 g/l, P < 0.001). However, fractional albumin synthesis rates were increased by 60% in patients (11.4 ± 1.0%/day) compared with controls (7.3 ± 0.4%/day, P < 0.01). Therefore, 1) head trauma induces opposite and large changes of protein synthesis in muscle and acute-phase hepatic proteins, probably mediated by cytokines, glucocorticoids, and other stress hormones, and 2) in these patients, hypoalbuminemia is not due to a depressed albumin synthesis.



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