scholarly journals Correlation between the urinary excretion of acid-soluble peptides, fractional synthesis rate of whole body proteins, and plasma immunoreactive insulin-like growth factor-l/somatomedin C concentration in the rat

1990 ◽  
Vol 63 (3) ◽  
pp. 515-520 ◽  
Author(s):  
Taek Jeong Nam ◽  
Tadashi Noguchi ◽  
Ryuhei Funabiki ◽  
Hisanori Kato ◽  
Yutaka Miura ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Growth Factor ◽  
Urinary Excretion ◽  
Whole Body ◽  
Synthesis Rate ◽  
Immunoreactive Insulin ◽  
Insulin Like Growth Factor ◽  
Body Protein ◽  
Somatomedin C ◽  
Plasma Immunoreactive Insulin

The relations between the urinary excretion of acid-soluble peptide (ASP)-form amino acids, the rate of whole body protein synthesis and plasma immunoreactive insulin-like growth factor-1/somatomedin C concentration were investigated in rats. The urinary ASP-form leucine plus valine excretion correlated well with the rate of whole body protein synthesis and with the plasma immunoreactive insulin-like growth factor-1 concentration. The results provide further evidence for the hypothesis that urinary excretion of ASP is an excellent index of the status of protein metabolism in animals.

scholarly journals Effect of dietary proteins on the plasma immunoreactive insulin-like growth factor-1/somatomedin C concentration in the rat

1990 ◽  
Vol 63 (3) ◽  
pp. 521-534 ◽  
Author(s):  
Sachiko Takahashi ◽  
Mikio Kajikawa ◽  
Tsutomu Umezawa ◽  
Shin-Ichiro Takahashi ◽  
Hisanorl Kato ◽  
...  
Keyword(s):  
Growth Factor ◽  
Immunoreactive Insulin ◽  
Dietary Proteins ◽  
Insulin Like Growth Factor ◽  
Somatomedin C ◽  
Plasma Immunoreactive Insulin

Incorporating turn-over in whole body protein retention ef.ciency in pigs

2005 ◽  
Vol 80 (1) ◽  
pp. 71-81 ◽  
Author(s):  
Z. Roux
Keyword(s):  
Protein Synthesis ◽  
Growth Factor ◽  
Hormonal Control ◽  
Whole Body ◽  
Insulin Like Growth Factor ◽  
Retention Efficiency ◽  
Body Protein ◽  
Protein Retention ◽  
Limit Value ◽  
Turn Over

The magnitude of the discrepancy between conventional regression estimates of protein retention efficiency and theoretical estimates of synthesis efficiency indicates a major contribution ascribable to protein turn-over in the generally accepted estimates. As protein turn-over is known to be influenced by diet, feeding level and degree of maturity, this suggests the development of an estimator of protein efficiency that can be adapted for such differences. Therefore, based on generally accepted formulas for growth description, a method of estimating protein retention efficiency was developed which is flexible enough to accommodate different diets, feeding levels and degrees of maturity. Moreover, a formula was derived to convert one type of estimate to the other by regarding constant efficiency as equivalent to variable efficiency at the mid point of the estimation interval. Increase in scientific depth to this descriptive approach is provided by a theoretical consideration of a possible mechanism of hormonal control of protein synthesis and breakdown, ultimately expressed as proportionalities to powers of whole body protein (P). Molecular considerations on cellular synthesis and breakdown indicate a difference between breakdown and synthesis powers equal to (2/9)Q. The factor (2/9) is indicated by an argument based on insulinlike growth factor derived activator diffusion attributes by nucleus and body tissue geometries, whileQis equal to the proportion of nuclei activated by insulin-like growth factor. This proportion is likely to be a function of the concentration of growth factor in the blood. Hence, a linear relationship between intake and blood insulin-like growth factor concentration suggests thatQcan be represented by a scaled transformation of intake, 0 ≤Q≤ 1, such that a value ofQ= 1 represents ad libitum intake on a suitable diet andQ= 0 intake at the maintenance requirement. The quantification of breakdown and synthesis power differences by (2/9)Qleads to kP= {1 + [1 − (P/α)(2/9)Q]−1/6}−1, for turn-over related protein retention efficiency (kP), with α the limit value of P at maturity, so that 0 ≤ (P/α) ≤ 1. Experimental estimates, derived from direct estimates of whole body protein synthesis and breakdown at predetermined levels of intake, are in excellent agreement with the theoretical (2/9)Qin the power associated with (P/α) in kP. Furthermore, conventional multiple regression retention efficiencies satisfactorily approximate the turn-over related retention efficiency that can be calculated at a given level of intake for the mid point of the interval covered by the regression estimates.

scholarly journals Insulin-like Growth Factor I (IGF-I) Increases Whole Body Protein Synthesis in Contrast to Insulin Which Reduces Proteolysis

1994 ◽  
Vol 3 (Supple5) ◽  
pp. 240-240
Author(s):  
David L. Russell-Jones ◽  
Marlot A. Umpleby ◽  
Tom D. Hennessy ◽  
Peter H. Sonksen
Keyword(s):  
Protein Synthesis ◽  
Growth Factor ◽  
Whole Body ◽  
Insulin Like Growth Factor ◽  
Body Protein ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Protein turnover in man measured with 15N: comparison of end products and dose regimes.

1978 ◽  
Vol 235 (2) ◽  
pp. E165 ◽  
Author(s):  
J C Waterlow ◽  
M H Golden ◽  
P J Garlick
Keyword(s):  
Protein Synthesis ◽  
Oral Dosage ◽  
Whole Body ◽  
Synthesis Rate ◽  
Obese Patients ◽  
Simple Method ◽  
Body Protein ◽  
End Products ◽  
Collection Period ◽  
Comparative Information

Whole-body protein synthesis was measured with [15N]glycine in malnourished and recovered infants and in obese patients. Comparisons were made: 1) between results obtained with single (S) and repeated (R) oral dosage of tracer; and 2) between urea and ammonia as end products. In the infants S and R gave similar values for the synthesis rate. With both methods of dosage, the values obtained with NH3 as end product were about two-thirds of those with urea. It is suggested that the cause of this result is that glycine contributes preferentially to the formation of urinary NH3. With NH3 as end product, a collection period of 12 h has been found to be suitable. With urea it is not possible to define an appropriate collection period. The combination of single dose of [15N]glycine with urinary NH3 as end product provides a simple method for measuring whole-body protein synthesis under clinical and field conditions. It can be repeated at short intervals and can give useful comparative information provided that conditions are carefully standardized. The reproducibility so far is +/- 13%.

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.

Impairment of albumin and whole body postprandial protein synthesis in compensated liver cirrhosis

2002 ◽  
Vol 282 (2) ◽  
pp. E304-E311 ◽  
Author(s):  
P. Tessari ◽  
R. Barazzoni ◽  
E. Kiwanuka ◽  
G. Davanzo ◽  
G. De Pergola ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Liver Cirrhosis ◽  
Disease Stage ◽  
Whole Body ◽  
Synthesis Rate ◽  
Albumin Concentration ◽  
Mixed Meal ◽  
Body Protein ◽  
Control Subjects ◽  
Class B

To investigate the anabolic effects of feeding in cirrhosis, we measured albumin fractional synthesis rate (FSR) and whole body protein synthesis in six nondiabetic patients with stable liver cirrhosis (three in the Child-Pugh classification Class A, three in Class B) and in seven normal control subjects, before and after administration of a 4-h mixed meal. Leucine tracer precursor-product relationships and whole body kinetics were employed at steady state. Basal levels of postabsorptive albumin concentration and FSR, whole body leucine rate of appearance, oxidation, and nonoxidative leucine disposal (NOLD, ≈protein synthesis) were similar in the two groups. However, after the meal, in the patients neither albumin FSR (from 8.5 ± 1.5 to 8.8 ± 1.8 %/day) nor NOLD (from 1.69 ± 0.22 to 1.55 ± 0.26 μmol · kg−1· min−1) changed ( P = nonsignificant vs. basal), whereas they increased in control subjects (albumin FSR: from 10.9 ± 1.5 to 15.9 ± 1.9 %/day, P < 0.002; NOLD: from 1.80 ± 0.14 to 2.10 ± 0.19 μmol · kg−1· min−1, P = 0.032). Thus mixed meal ingestion did not stimulate either albumin FSR or whole body protein synthesis in compensated liver cirrhosis. The mechanism(s) maintaining normoalbuminemia at this disease stage need to be further investigated.

Effect of spaceflight on human protein metabolism

1993 ◽  
Vol 264 (5) ◽  
pp. E824-E828 ◽  
Author(s):  
T. P. Stein ◽  
M. J. Leskiw ◽  
M. D. Schluter
Keyword(s):  
Protein Synthesis ◽  
Nitrogen Balance ◽  
Protein Metabolism ◽  
Space Shuttle ◽  
Single Pulse ◽  
Whole Body ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Body Protein ◽  
Space Shuttle Columbia

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.

scholarly journals Increased plasma Gln and Leu Raand inappropriately low muscle protein synthesis rate in AIDS wasting

1998 ◽  
Vol 275 (4) ◽  
pp. E577-E583 ◽  
Author(s):  
Kevin E. Yarasheski ◽  
Jeffrey J. Zachwieja ◽  
Jennifer Gischler ◽  
Jan Crowley ◽  
Mary M. Horgan ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Whole Body ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Asymptomatic Group ◽  
Body Protein ◽  
Asymptomatic Subjects ◽  
Muscle Protein Synthesis Rate

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.

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