The influence of the nutritive value of proteins on the level of protein synthesis in vitro in rat skeletal muscle

Omstedt, Per T.; Decken, Alexandra von der

doi:10.1079/bjn19720115

Cited by 32 publications

(8 citation statements)

References 11 publications

(3 reference statements)

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“…table II with tables IV and V). This is in agreement with previous results on skeletal muscle ribosomes [7,11]. Differences in protein synthesis between dietary groups of rats were independent of the radioactive amino acid used in the assay.…”

Section: General Views On the Evaluation O F Protein Synthesissupporting

confidence: 82%

“…The results are based on calculations made with casein supplemented with methionine, or a complete amino acid mixture as standards, and are the following: (a) Ribosomal activity is the most sus ceptible to alterations in environmental conditions. It is changed by nitrogen sources known to be restricted in nutritional quality [7,[11][12][13]. (b) A decrease in ribosomal activity is followed by changes in liver size and, there fore, by protein synthesis per total liver wet weight.…”

Section: Resultsmentioning

confidence: 99%

“…Investigations dealing with intracellular protein metabolism have revealed that the activity level of protein synthesis in liver and skeletal muscle is deter mined by the quality of the dietary proteins [3][4][5][6][7][11][12][13]. In skeletal muscle, a positive correlation was obtained between the biological value of the dietary proteins and protein synthesis; but there can be discrepancies between protein synthesis and protein efficiency ratio determinations [7,12].…”

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confidence: 99%

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Effect of Dietary Protein and Amino Acid Mixture on Protein Synthesis <i>in vitro </i>in Rat Liver

A¹,

Pt²

1974

Ann Nutr Metab

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Rats received for 6 consecutive days a diet containing 20% of the protein under test, or an equivalent amount of amino acid mixture. Protein synthesis of liver ribosomes was determined by measuring the incorporation of ¹⁴C-labelled amino acids into protein in vitro. Protein synthesis was related to (a) ribosomal RNA (mg), (b) wet weight of liver (g), (c) total liver wet weight, and (d) liver per 100 g body weight. The following five nitrogen sources were studied. Preparations of the microalgae Scenedesmus obliquus, Spirulina platensis; wheat gluten, amino acid mixtures deficient in either lysine or methionine. When compared to a standard diet containing a high-quality protein (casein supplemented with methionine), or a complete amino acid mixture, the five nitrogen sources gave relative reductions in protein synthesis. (1) The primary effect was on activity per unit of ribosomal RNA. This was obtained by giving rats one of the following preparations; Scenedesmus obliquus, Spirulina platensis, wheat gluten, or an amino acid mixture deficient in lysine or methionine. (2) Due to a decrease in liver weight, an effect on activity per total liver wet weight was observed after feeding Spirulina platensis, wheat gluten or the amino acid-deficient diets. (3) A smaller number of ribosomes are responsible for a lower protein synthesis per gram liver after feeding wheat gluten, or the amino acid-deficient diets. A less pronounced change was obtained with Spirulina platensis. (4) Liver activity related to 100 g body weight was lower with wheat gluten, the amino acid-deficient diets and Spirulina platensis. Activity was restored within 1 day by giving a complete amino acid mixture after 6 days of lysine deficiency.

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Section: General Views On the Evaluation O F Protein Synthesissupporting

confidence: 82%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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Effect of Dietary Protein and Amino Acid Mixture on Protein Synthesis <i>in vitro </i>in Rat Liver

A¹,

Pt²

1974

Ann Nutr Metab

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“…The Mg** concentration of the medium was reduced to 0.005 M. l or incubation experiments cell sap was passed through a column of Sephadex G-25, to remove small molecular weight components including amino acids (18). (11). Two ribosomal concentrations were incubated, each in duplicate.…”

Section: Preparation O F Rat Liver Cell Sapmentioning

confidence: 99%

Structural and Functional Changes in Ribosomes from Ischemic Liver in the Dog: Effects of Short-Term Hepatic Artery Ligation and Hemorrhagic Shock

Hasselgren¹,

Almersjö²,

Gustavsson³

et al. 1980

Eur Surg Res

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Structure and function of isolated liver ribosomes from 10 dogs subjected to 1 h of hepatic artery ligation (HAL) or hemorrhagic shock were studied. A shift of polyribosomes to monoribosomes and a decreased capacity to incorporate amino acids into proteins were seen in both experimental conditions. The effects were more pronounced in hemorrhagic shock. Both structural and functional changes were reversible after HAL. In the shock experiments a slight increase of the ribosomal activity was seen after reinfusion but the initial values were not reached during the 2 h after the shock period. Some of the underlying mechanisms of altered ribosomal structure and function in liver ischemia are discussed.

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“…The effect on ribosomal activity in the absence of poly U might be an effect oninitiationor termination of polypeptide formation. At the 10 mmol-MgC1, concentration which has to be used in a poly-U-dependent system, initiation is independent of ribosomal factors which otherwise catalyse this reaction (Shafritz, Prichard, Gilbert & Anderson, 1970).…”

Section: Discussionmentioning

confidence: 99%

Formation of linoleic acid in the rat colon

Sklan

Budowski

1972

BJN

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I. The amino acid incorporating activity of skeletal muscle ribosomes was studied in rats under various nutritional conditions using labelled amino acids.2. Ribosomes were obtained from rats that were given a protein-free diet for 5 d followed by a high-protein diet containing casein, gelatin or wheat gluten for 16.5 h and from others that were given one of these protein-containing diets or one containing protein from polished rice for 6 d.3. The levcl of isotope incorporation relative to RNA was somewhat higher when the protein source given for 16.5 h was a good-quality protein such as casein than with gelatin or wheat gluten, but fine discrimination between proteins was not considered to be feasible with this system. 4.In the rats that were given the protein-containing diets for 6 d the differences were more pronounced and the amino acid incorporating activity was correlated with the biological value of the protein.In previous work (von der Decken, 1967Decken, , 1968aDecken, , b, 1969a it was demonstrated that the activity of mammalian ribosomes in incorporating amino acids into protein is sensitive to short-term protein starvation of the animals. Feeding rats with protein after the depletion period enhanced the incorporating activity. It was observed that not only the liver ribosomes, but also the ribosomes prepared from skeletal muscle, were affected by the diet (von der Decken & Omstedt, 1970). In liver the effect of a protein-free carbohydrate-rich diet in depressing protein synthesis is masked to a certain extent by a simultaneous increase in enzymes involved in liver gluconeogenesis (Kaplan & Pitot, 1970). On the other hand, in skeletal muscle the changes are less complex and the influence of protein malnutrition on the mechanism of polypeptide formation is better defined in its effect.Whereas in earlier work a comparison was made between a protein-free diet and a diet rich in protein of high biological value (BV), the present investigation is concerned with the effect on protein synthesis of diets containing proteins of different BV. As a preliminary, the nutritional conditions have been established that give statistically significant differences in the specific activity of the incorporation of amino acids into protein after a reasonably short period of feeding with the test diets. E X P E R I M E N T A LMaterials. Chemicals were of AR grade wherever possible. The sources were given in detail previously (von der Decken, 1968a, 1 9 6 9~) .In addition,

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The influence of the nutritive value of proteins on the level of protein synthesis in vitro in rat skeletal muscle

Cited by 32 publications

References 11 publications

Effect of Dietary Protein and Amino Acid Mixture on Protein Synthesis <i>in vitro </i>in Rat Liver

Effect of Dietary Protein and Amino Acid Mixture on Protein Synthesis <i>in vitro </i>in Rat Liver

Structural and Functional Changes in Ribosomes from Ischemic Liver in the Dog: Effects of Short-Term Hepatic Artery Ligation and Hemorrhagic Shock

Formation of linoleic acid in the rat colon

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