Protein synthesis rates in skin components and skeletal muscle of sheep selected for divergent clean fleece weight in response to below- and above-maintenance nutrition

2007 ◽  
Vol 58 (11) ◽  
pp. 1031 ◽  
Author(s):  
L. Li ◽  
S. M. Liu ◽  
V. H. Oddy ◽  
J. V. Nolan
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Feed Intake ◽  
Synthesis Rate ◽  
Breeding Values ◽  
Fractional Synthesis Rate ◽  
Feeding Level ◽  
Fractional Synthesis ◽  
Fleece Weight ◽  
Estimated Breeding Values

Protein metabolism in skin and muscle was studied in Merino wethers selected for high (F+, n = 10) or low (F–, n = 10) estimated breeding values for clean fleece weight, but with similar estimated breeding values for liveweight and fibre diameter, raised to 20 months of age under the same conditions, and then offered two levels of nutrition (0.8 or 1.8 × maintenance) for 37 days. Over 37 days, F+ sheep had greater rate of wool production, liveweight gain, and had greater eye-muscle and fat depth than F– sheep (P < 0.05). Fractional synthesis rates of protein (%/day) in the epidermis, dermis, whole skin and muscle were affected by both feeding level (P < 0.05) and genotype (P < 0.05). The fractional synthesis rates of protein were greater (P < 0.05) in F+ sheep at both levels of intake. There was an interaction (P < 0.01) between genotype and feeding level for the protein fractional synthesis rate in muscle, where F+ sheep were more responsive to higher feed intake. Muscle of F– sheep responded to increased amino acid supply by reducing the rate of protein degradation without altering synthesis rate; whereas muscle of F+ sheep responded by increasing the rates of both protein synthesis and degradation. The overall muscle fractional synthesis rate (1.6%/day) was ~7-times lower than the skin fractional synthesis rate (10.8%/day) in these animals (P < 0.01). F+ sheep had a higher rate of protein synthesis in dermis and whole skin to support their higher wool protein accretion at both levels of feed intake. Muscle protein synthesis rate was greater in F+ sheep offered above-maintenance metabolisable energy (ME) intake than those given below-maintenance ME intake but was unaffected by ME intake in F– sheep. The results indicate that selection for wool growth not only affects production of wool and the wool follicle, but also affects the rate of protein turnover in components of the skin and skeletal muscle.

scholarly journals The effects of breed and level of nutrition on whole-body and muscle protein metabolism in pure-bred Aberdeen Angus and Charolais beef steers

2000 ◽  
Vol 84 (3) ◽  
pp. 275-284 ◽  
Author(s):  
G. E. Lobley ◽  
K. D. Sinclair ◽  
C. M. Grant ◽  
L. Miller ◽  
D. Mantle ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Live Weight ◽  
Whole Body ◽  
Synthesis Rate ◽  
Eating Quality ◽  
Eye Muscle ◽  
Fractional Synthesis Rate ◽  
Fractional Synthesis

Eighteen pure-bred steers (live weight 350 kg) from each of two breeds, Aberdeen Angus (AA) and Charolais (CH), were split into three equal groups (six animals each) and offered three planes of nutrition during a 20-week period. The same ration formulation was offered to all animals with amounts adjusted at 3-week intervals to give predicted average weight gains of either 1·0 kg/d (M/M group) or 1·4 kg/d (H/H group). The remaining group (M/H) were offered the same amount of ration as the M/M group until 10 weeks before slaughter when the ration was increased to H. Data on animal performance, carcass characteristics and fibre-type composition in skeletal muscle are presented elsewhere (; ). On three occasions (17, 10 and 2 weeks before slaughter) the animals were transferred to metabolism stalls for 1 week, during which total urine collection for quantification of Nτ-methylhistidine (Nτ-MeH) elimination was performed for 4 d. On the last day, animals were infused for 11 h with [2H5] phenylalanine with frequent blood sampling (to allow determination of whole-body phenylalanine flux) followed by biopsies from m. longissimus lumborum and m. vastus lateralis to determine the fractional synthesis rate of mixed muscle protein. For both breeds, the absolute amount of Nτ-MeH eliminated increased with animal age or weight (P < 0·001) and was significantly greater for CH steers, at all intake comparisons, than for AA (P < 0·001). Estimates of fractional muscle breakdown rate (FBR; calculated from Nτ-MeH elimination and based on skeletal muscle as a fixed fraction of live weight) showed an age (or weight) decline for M/M and H/H groups of both breeds (P < 0·001). FBR was greater for the H/H group (P = 0·044). The M/H group also showed a lower FBR for the first two measurement periods (both at M intake) but increased when intake was raised to H. When allowance was made for differences in lean content (calculated from fat scores and eye muscle area in carcasses at the end of period 3), there were significant differences in muscle FBR with intake (P = 0·012) but not between breed. Whole-body protein flux (WBPF; g/d) based on plasma phenylalanine kinetics increased with age or weight (P < 0·001) and was similar between breeds. The WBPF was lower for M/M compared with H/H (P < 0·001) based on either total or per kg live weight0·75. Muscle protein fractional synthesis rate (FSR) declined with age for both breeds and tended to be higher at H/H compared with M intakes (intake × period effects, P < 0·05). Changing intake from M to H caused a significant increase (P < 0·001) in FSR. The FSR values for AA were significantly greater than for CH at comparable ages (P = 0·044). Although FSR and FBR responded to nutrition, these changes in protein metabolism were not reflected in differences in meat eating quality (Sinclair et al. 2000).

scholarly journals Contribution of whole-body protein synthesis to basal metabolism in layer and broiler chickens

1987 ◽  
Vol 57 (2) ◽  
pp. 269-277 ◽  
Author(s):  
T. Muramatsu ◽  
Y. Aoyagi ◽  
J. Okumura ◽  
I. Tasaki
Keyword(s):  
Protein Synthesis ◽  
Broiler Chickens ◽  
Whole Body ◽  
Synthesis Rate ◽  
Body Protein ◽  
Fractional Synthesis Rate ◽  
Degradation Rates ◽  
Fractional Synthesis ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

1. The effect of starvation on whole-body protein synthesis and on the contribution of protein synthesis to basal metabolic rate was investigated in young chickens (Expt 1). Strain differences between layer and broiler chickens in whole-body protein synthesis and degradation rates were examined when the birds were starved (Expt 2).2. In Expt 1, 15-d-old White Leghorn male chickens were used, while in Expt 2 Hubbard (broiler) and White Leghorn (layer) male chickens at 14 d of age were used. They were starved for 4 d, and heat production was determined by carcass analysis after 2 and 4 d of starvation. Whole-body protein synthesis rates were measured on 0, 2 and 4 d of starvation (Expt 1), and on 0 and 4 d of starvation (Expt 2).3. The results showed that starving reduced whole-body protein synthesis in terms of fractional synthesis rate and the amount synthesized. Whole-body protein degradation was increased by starvation both in terms of fractional synthesis rate and the amount degraded on a per kg body-weight basis.4. Reduced fractional synthesis rate of protein in the whole body was accounted for by reductions in both protein synthesis per unit RNA and RNA:protein ratio.5. In the fed state, whole-body protein synthesis and degradation rates, whether expressed as fractional rates or amounts per unit body-weight, tended to be higher in layer than in broiler chickens. In the starved state, the difference in the rate of protein synthesis between the two strains virtually disappeared, while the degradation rates were higher in layer than in broiler birds.6. Based on the assumed value of 3.56 kJ/g protein synthesized (Waterlow et al. 1978), the heat associated with whole-body protein synthesis in the starved state was calculated to range from 14 to 17% of the basal metabolic rate with no strain difference between layer and broiler chickens.

scholarly journals Proteome-wide muscle protein fractional synthesis rates predict muscle mass gain in response to a selective androgen receptor modulator in rats

2016 ◽  
Vol 310 (6) ◽  
pp. E405-E417 ◽  
Author(s):  
Mahalakshmi Shankaran ◽  
Todd W. Shearer ◽  
Stephen A. Stimpson ◽  
Scott M. Turner ◽  
Chelsea King ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Androgen Receptor ◽  
Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Synthesis Rate ◽  
Muscle Proteins ◽  
Receptor Modulator ◽  
Fractional Synthesis

Biomarkers of muscle protein synthesis rate could provide early data demonstrating anabolic efficacy for treating muscle-wasting conditions. Androgenic therapies have been shown to increase muscle mass primarily by increasing the rate of muscle protein synthesis. We hypothesized that the synthesis rate of large numbers of individual muscle proteins could serve as early response biomarkers and potentially treatment-specific signaling for predicting the effect of anabolic treatments on muscle mass. Utilizing selective androgen receptor modulator (SARM) treatment in the ovariectomized (OVX) rat, we applied an unbiased, dynamic proteomics approach to measure the fractional synthesis rates (FSR) of 167–201 individual skeletal muscle proteins in triceps, EDL, and soleus. OVX rats treated with a SARM molecule (GSK212A at 0.1, 0.3, or 1 mg/kg) for 10 or 28 days showed significant, dose-related increases in body weight, lean body mass, and individual triceps but not EDL or soleus weights. Thirty-four out of the 94 proteins measured from the triceps of all rats exhibited a significant, dose-related increase in FSR after 10 days of SARM treatment. For several cytoplasmic proteins, including carbonic anhydrase 3, creatine kinase M-type (CK-M), pyruvate kinase, and aldolase-A, a change in 10-day FSR was strongly correlated ( r2 = 0.90–0.99) to the 28-day change in lean body mass and triceps weight gains, suggesting a noninvasive measurement of SARM effects. In summary, FSR of multiple muscle proteins measured by dynamics of moderate- to high-abundance proteins provides early biomarkers of the anabolic response of skeletal muscle to SARM.

Ventricular pacing attenuates but does not reverse cardiac atrophy and an isomyosin shift in the rat heart

1994 ◽  
Vol 267 (6) ◽  
pp. H2149-H2154 ◽  
Author(s):  
D. L. Geenen ◽  
A. Malhotra ◽  
P. M. Buttrick ◽  
J. Scheuer
Keyword(s):  
Protein Synthesis ◽  
Protein Content ◽  
Rat Heart ◽  
Left Ventricular ◽  
Synthesis Rate ◽  
Fractional Synthesis Rate ◽  
Cardiac Atrophy ◽  
Wet Weight ◽  
Fractional Synthesis

The heterotopically transplanted rat heart (TH) undergoes rapid muscle atrophy and a concurrent shift from alpha- to beta-myosin heavy chain (MHC) by 1 wk after surgery. In the current experiments, TH were continuously paced (420 beats/min) for 1 wk beginning 24 h after surgery or for 1 wk beginning 14 days after surgery to determine the role of increased heart rate in preventing or reversing cardiac atrophy. Left ventricular (LV) wet weight (283 vs. 256 mg paced vs. nonpaced) and protein content (32 vs. 23 mg paced vs. nonpaced, P < 0.05) were significantly elevated in TH paced 1 wk after surgery but were unchanged (211 vs. 198 mg and 24 vs. 23 mg LV wet wt and protein content, respectively) in TH paced 2 wk after surgery. Total cardiac protein synthesis in the TH paced immediately after surgery was increased compared with the corresponding nonpaced hearts (5.6 vs. 4.0 mg.mg LV wet wt-1.day-1, P < 0.05), while in the TH, where pacing was initiated 2 wk after surgery, it was unchanged (3.6 vs. 3.7 mg.mg LV wet wt-1.day-1). Fractional synthesis rate was elevated in TH and was not altered by pacing. Pacing the TH also attenuated the shift in alpha-MHC in the first 7 days after surgery but did not reverse the shift 2 wk later. The increase in protein synthesis combined with an unchanged fractional synthesis rate suggests that pacing attenuates cardiac mass by decreasing protein degradation and that once the atrophic process is established, neither synthesis rate nor isomyosin shift can be altered by continuous pacing.

Measurement of human mixed muscle protein fractional synthesis rate depends on the choice of amino acid tracer

2007 ◽  
Vol 293 (3) ◽  
pp. E666-E671 ◽  
Author(s):  
Gordon I. Smith ◽  
Dennis T. Villareal ◽  
Bettina Mittendorfer
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Tissue ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Fat Free Mass ◽  
Synthesis Rate ◽  
Tissue Fluid ◽  
Fractional Synthesis Rate ◽  
Fractional Synthesis

The goal of this study was to discover whether using different tracers affects the measured rate of muscle protein synthesis in human muscle. We therefore measured the mixed muscle protein fractional synthesis rate (FSR) in the quadriceps of older adults during basal, postabsorptive conditions and mixed meal feeding (70 mg protein·kg fat-free mass−1·h−1 × 2.5 h) by simultaneous intravenous infusions of [5,5,5-2H3]leucine and either [ring-13C6]phenylalanine or [ring-2H5]phenylalanine and analysis of muscle tissue samples by gas chromatography-mass spectrometry. Both the basal FSR and the FSR during feeding were ∼20% greater ( P < 0.001) when calculated from the leucine labeling in muscle tissue fluid and proteins (fasted: 0.063 ± 0.005%/h; fed: 0.080 ± 0.007%/h) than when calculated from the phenylalanine enrichment data (0.051 ± 0.004 and 0.066 ± 0.005%/h, respectively). The feeding-induced increase in the FSR (∼20%; P = 0.011) was not different with leucine and phenylalanine tracers ( P = 0.69). Furthermore, the difference between the leucine- and phenylalanine-derived FSRs was independent of the phenylalanine isotopomer used ( P = 0.92). We conclude that when using stable isotope-labeled tracers and the classic precursor product model to measure the rate of muscle protein synthesis, absolute rates of muscle protein FSR differ significantly depending on the tracer amino acid used; however, the anabolic response to feeding is independent of the tracer used. Thus different precursor amino acid tracers cannot be used interchangeably for the evaluation of muscle protein synthesis, and data from studies using different tracer amino acids can be compared qualitatively but not quantitatively.

Protein metabolism in skin and muscle of sheep selected for or against staple strength

2000 ◽  
Vol 51 (5) ◽  
pp. 541 ◽  
Author(s):  
N. R. Adams ◽  
S. M. Liu ◽  
J. R. Briegel ◽  
J. C. Greeff
Keyword(s):  
Growth Rate ◽  
Protein Synthesis ◽  
Synthesis Rate ◽  
Deuterated Water ◽  
Feeding Level ◽  
Fractional Rate ◽  
Wool Growth ◽  
Fractional Synthesis ◽  
Selection For ◽  
Staple Strength

Two experiments were carried out to determine the mechanisms underlying the reduced effect of nutritional status on wool growth rate in Merino sheep that have been selected for high staple strength (SS). In Expt 1, each group of 6 young sheep of SS+ and SS– genotypes were fed at 0.4 or 1.1 times maintenance, and in Expt 2, groups of 8 sheep of each genotype were fed at 1.1 and 1.8 times maintenance. In both experiments, rates of protein synthesis in skin, muscle, gut, rumen, and liver were determined using a flooding dose of labelled phenylalanine. Feed intake and the digestibility of feed were not affected by genotype. Neither dissection of the carcasses at slaughter, nor deuterated water analysis in Expt 1, detected any differences between the genotypes in body composition. The feeding level affected the total daily amount of protein synthesised in all the organs examined, and the fractional rate of protein synthesis was affected by feeding level in all organs except the liver. The fractional synthesis rate of protein was less responsive to feeding level in the SS+ sheep in both skin and muscle (P < 0.05), but not in the liver, jejunum, or rumen. Total protein synthesis in muscle, and the estimated rate of protein degradation, were also less responsive to feeding level in the SS+ sheep (P < 0.05). We conclude that sheep genetically selected for high or low SS have altered local mechanisms in both skin and muscle that control the way they respond to nutrition. These findings provide a mechanism by which selection for wool growth rate also affects body metabolism.

Assessment of the mathematical issues involved in measuring the fractional synthesis rate of protein using the flooding dose technique

1993 ◽  
Vol 84 (2) ◽  
pp. 177-183 ◽  
Author(s):  
David L. Chinkes ◽  
Judah Rosenblatt ◽  
Robert R. Wolfe
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Intracellular Concentration ◽  
Upper And Lower Bounds ◽  
Constant Infusion ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Underlying Assumption ◽  
Fractional Synthesis Rate ◽  
Fractional Synthesis

1. The fractional synthesis rate of protein is commonly measured by either the constant infusion method or the flooding dose method. The two methods often give different results. 2. An underlying assumption of the traditional flooding dose formula is that the protein synthesis rate is not stimulated by the flooding dose. A new formula for calculation of the fractional synthesis rate is derived with the alternative assumption that the protein synthesis rate is stimulated by an amount proportional to the change in the intracellular concentration of the infused amino acid. The alternative formula is: where EB and EF are the enrichments of bound and free amino acid, respectively (atom per cent excess), and C=1-(EF/EI), where EI is the enrichment of the infusate. This approach defines the lowest possible value for the fractional synthesis rate. The traditional equation gives a maximal value for the fractional synthesis rate. 3. When data from the literature are considered, the fractional synthesis rate of muscle protein as calculated by the constant infusion technique falls between the values of fractional synthesis rate calculated by the two flooding dose formulae when leucine is the tracer, suggesting that a flooding dose of leucine exerts a stimulatory effect on the rate of protein synthesis, but that the increase is not as great as the increase in the intracellular concentration of leucine. 4. The precision of the formula for the calculation of fractional synthesis rate is limited by the accuracy of the underlying assumptions regarding the effect of the flooding dose on the fractional synthesis rate. At present, the best approach would appear to be the use of both equations to calculate the upper and lower bounds of the true fractional synthesis rate.

scholarly journals The effects of endotoxaemia on protein metabolism in skeletal muscle and liver of fed and fasted rats

1986 ◽  
Vol 235 (2) ◽  
pp. 329-336 ◽  
Author(s):  
M M Jepson ◽  
J M Pell ◽  
P C Bates ◽  
D J Millward
Keyword(s):  
Protein Synthesis ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Synthesis Rate ◽  
Liver Protein ◽  
Fractional Synthesis Rate ◽  
Protein Mass ◽  
Fractional Synthesis ◽  
Fasted Rats

The response of muscle and liver protein metabolism to either a single or three successive daily injections of an endotoxin (Escherichia coli lipopolysaccharide, serotype 0127 B8; 1 mg/ml, 0.3 mg/100 g body wt.) was studied in vivo in the fed rat, and at 24 and 30 h after endotoxin treatment during fasting. In the fed rats there was a catabolic response in muscle, owing to a 60-100% increase in muscle protein degradation rate, and a 52% fall in the synthesis rate. Although there was a 20% decrease in food intake, the decrease in protein synthesis was to some extent independent of this, since rats treated with endotoxin and fasted also showed a lower rate of muscle protein synthesis, which was in excess of the decrease caused by fasting alone. The mechanism of this decreased protein synthesis involved decreased translational activity, since in both fed and fasted rats there was a decreased rate of synthesis per unit of RNA. This occurred despite the fact that insulin concentrations were either maintained or increased, in the fasted rats, to those observed in fed rats. In the liver total protein mass was increased in the fed rats by 16% at 24 h, and the fractional synthesis rate at that time was increased by 35%. In rats fasted after endotoxin treatment the liver protein mass was not decreased as it was in the control fasted rats, and the fractional synthesis rate was increased by 22%. In both cases the increased synthesis rate reflected an elevated hepatic RNA concentration. The extent of this increase in hepatic protein synthesis was sufficient at one point to compensate for the fall in estimated muscle protein synthesis, so that the sum total in the two tissues was maintained.

scholarly journals Comparison of bolus injection and constant infusion methods for measuring muscle protein fractional synthesis rate in humans

Metabolism ◽  
2014 ◽  
Vol 63 (12) ◽  
pp. 1562-1567 ◽  
Author(s):  
Demidmaa Tuvdendorj ◽  
David L. Chinkes ◽  
John Bahadorani ◽  
Xiao-jun Zhang ◽  
Melinda Sheffield-Moore ◽  
...  
Keyword(s):  
Bolus Injection ◽  
Muscle Protein ◽  
Constant Infusion ◽  
Synthesis Rate ◽  
Fractional Synthesis Rate ◽  
Fractional Synthesis

Evidence for increased synthesis of lipoprotein(a) in the nephrotic syndrome.

1998 ◽  
Vol 9 (8) ◽  
pp. 1474-1481
Author(s):  
M G De Sain-Van Der Velden ◽  
D J Reijngoud ◽  
G A Kaysen ◽  
M M Gadellaa ◽  
H Voorbij ◽  
...  
Keyword(s):  
Nephrotic Syndrome ◽  
Synthesis Rate ◽  
Fractional Synthesis Rate ◽  
Lipoprotein A ◽  
Control Subjects ◽  
Apolipoprotein A ◽  
Catabolic Rate ◽  
Fractional Synthesis ◽  
The Mean

In patients with the nephrotic syndrome, markedly increased levels of lipoprotein(a) (Lp(a)) concentration have been frequently reported, and it has been suggested that this may contribute to the increased cardiovascular risk in these patients. The mechanism, however, is not clear. In the present study, in vivo fractional synthesis rate of Lp(a) was measured using incorporation of the stable isotope 13C valine. Under steady-state conditions, fractional synthesis rate equals fractional catabolic rate (FCR). FCR of Lp(a) was estimated in five patients with the nephrotic syndrome and compared with five control subjects. The mean plasma Lp(a) concentration in the patients (1749+/-612 mg/L) was higher than in control subjects (553+/-96 mg/L). Two patients were heterozygous for apolipoprotein(a) (range, 19 to 30 kringle IV domains), whereas all control subjects were each homozygous with regard to apolipoprotein(a) phenotype (range, 18 to 28 kringle IV domains). The FCR of Lp(a) was comparable between control subjects (0.072+/-0.032 pools/d) and patients (0.064+/-0.029 pools/d) despite the wide variance in plasma concentration. This suggests that differences in Lp(a) levels are caused by differences in synthesis rate. Indeed, the absolute synthetic rate of Lp(a) correlated directly with plasma Lp(a) concentration (P < 0.0001) in all subjects. The present results demonstrate that increased synthesis, rather than decreased catabolism, causes elevated plasma Lp(a) concentrations in the nephrotic syndrome.

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