The mode of action of dietary carbohydrate on protein metabolism

Munro, Hamish N.; Black, J.G.; Thomson, W. S. T.

doi:10.1079/bjn19590061

Cited by 63 publications

(16 citation statements)

References 30 publications

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“…The decrease in concentration of plasma EAA was primarily due to reduced supply of these amino acids but it was also related to energy supply, because addition of extra energy to the low-egg-protein diet resulted in reduction of plasma EAAs. Further evidence that decrease in the levels of plasma EAAs in protein deficiencies may be intensified by supply of excess energy is as MA FREE AMINO ACIDS IN MEN 305 follows: (i) LUNN et al (8) observed hyperinsulinemia resulting from ingestion of high-carbohydrate meals during the early stage of kwashiorkor and suggested that utilization of amino acids in tissues was enhanced in this condition; (ii) We found previously (9) that the nitrogen balance and NPU observed with submaintenance N intakes were greatly affected by the protein sparing effect of energy intake; (iii) MUNRO et al (20) showed that the lowered levels of plasma amino acids observed in subjects loaded with glucose were due to enhanced utilization of the amino acids in the muscle through the action of insulin; and (iv) recently, GRIMBLE and WHITEHEAD (7) also reported similar findings to (iii), in patients with kwashiorkor after administration of glucose.…”

Section: Discussionmentioning

confidence: 99%

Effect of low-protein diets on free amino acids in plasma of young men: Effect of protein quality with maintenance or excess energy intake.

Fujita

Yoshimura

Inoue

1978

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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Section: Discussionmentioning

confidence: 99%

Effect of low-protein diets on free amino acids in plasma of young men: Effect of protein quality with maintenance or excess energy intake.

Fujita

Yoshimura

Inoue

1978

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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“…Munro, Black & Thomson (1959) have suggested that carbohydrate causes deposition of amino acids in the muscles, with reduction of liver protein. The liver is generally accepted as the site of serum-albumin production and the above suggestion might explain the increased rate of fall of serum albumin in animals fed on the higher carbohydrate diets at suboptimal intakes.…”

Section: Resultsmentioning

confidence: 99%

The influence of dietary carbohydrate intake on serum protein levels

Coles¹,

Macdonald²

1963

The Journal of Physiology

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The concept of carbohydrate as a protein-sparer is long established and it would be expected that the addition of carbohydrate to low-protein diets would result in an amelioration of the effects of protein malnutrition. The experiments to be described were designed to test the effect on the serum proteins of varying the carbohydrate content of a diet of fixed lowprotein intake. The type of carbohydrate used was also varied. The results suggest that under certain circumstances carbohydrates seem to have an effect which is the reverse of protein-sparing. METHODSTwenty-two adult rabbits of approximately 2 kg weight were given a diet consisting mainly of stock green food in powder form, to which was added varying amounts of different carbohydrates. The carbohydrates used were maize starch, dried liquid glucose B.P.C., and sucrose. The composition of the diet and method of feeding were so arranged that paired animals of similar weight ate the same small amount of protein but varying amounts of carbohydrate (Macdonald, 1962). The carbohydrate was fed at two levels, 'high', 65% by weight of the dry diet and 'low' 36 % of the dry diet. The animals were killed when a third of the initial body weight had been lost. Serum samples were examined at three-weekly intervals, blood being obtained from the marginal vein of the ear. The serum proteins were separated by paper electrophoresis in a vertical tank with Whatman No. 31 extra thick paper. Samples of 0 05 ml. serum were run for 16 hr at a current of 0-25 mA/cm. width of paper. A barbitone:sodium barbitone buffer of pH 86 was used throughout. The strips were dried at 1100 C and stained with 0-01 % bromophenol blue after the method of Block, Durrum & Zweig (1955). The indidivual protein fractions were then estimated by the method of Levin & Oberholzer (1953), and the sum of the fractions was checked against the total serum protein as estimated on 0-1 ml. samples with a micro-Kjeldahl technique. All results were expressed as g protein/100 ml. serum. RESULTSThe results have been expressed as the slope of the regression line of length of time on the diet (in weeks) plotted against the concentration of the protein in g/100 ml. serum. Findings are considered statistically significant when P = < 005. Physiol. 165 21

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“…Therefore, nitrogen retention dose not necessarily mean protein anabolism only, such as synthesis of protein. It has been reported that the protein-sparing action might be attributable to protein synthesis in the muscle (18). However, the reduction of urinary nitrogen excretion would be involved in more complicated biochemical changes.…”

Section: Discussionmentioning

confidence: 99%

Nitrogen balance and hepatic gluconeogenesis in rats fed on diets containing various proportions of carbohydrate and fat.

Takase

Morimoto

Moriuchi

et al. 1981

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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SummaryThis study was conducted to investigate the effects of various proportions of dietary carbohydrate and fat in diet on protein and carbohydrate metabolism. The growth rate, nitrogen balance, urinary and serum urea levels, and the activities of key ureogenic and gluconeogenic enzymes in the livers were examined in the weanling and growing rats. The rats were raised on a 20% casein diet containing various proportions of carbohydrate and fat, viz. 30% and 50%, 50% and 30%, 60% and 20% or 70% and 10% as calorie percent, respectively, for 10 days. For both weanling and growing rats, the growth rate was unaffected by the alteration in the proportions of carbohydrate and fat in the diets. However, in the rats fed on the 30% carbohydrate-50% fat diet, the urinary excrection of nitrogen and urea were reduced in both groups and these findings were reflected in the reduced serum urea level. Arginase activity decreased. In contrast, glucose-6-phosphatase activity was en hanced in the animals of the 30% carbohydrate-50% fat diet group as compared to the other groups. These results suggest that a low carbohydrate-high fat diet causes the reduction of urea formation and the enhancement of glucose formation at a fixed level of protein in the diets in weanling as well as in growing rats.

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The mode of action of dietary carbohydrate on protein metabolism

Cited by 63 publications

References 30 publications

Effect of low-protein diets on free amino acids in plasma of young men: Effect of protein quality with maintenance or excess energy intake.

Effect of low-protein diets on free amino acids in plasma of young men: Effect of protein quality with maintenance or excess energy intake.

The influence of dietary carbohydrate intake on serum protein levels

Nitrogen balance and hepatic gluconeogenesis in rats fed on diets containing various proportions of carbohydrate and fat.

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