Effect of feeding a high protein diet on amino acid uptake into rat intestinal brush border membrane vesicles

Wolffram, Siegfried; Scharrer, E.

doi:10.1007/bf00670533

Cited by 33 publications

(13 citation statements)

References 15 publications

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“…However, under excess-energy diets (including protein), it is no longer necessary to retain so much amino-N and essential amino acids. Amino acids are used for energy when in relative excess (20,21) , but the even higher availability of energy from other sources strongly limits our metabolic machinery to do so (22) . Amino acid catabolism tends to retain 2-amino-N, largely because most amino acid hydrocarbon skeletons are oxidised after transamination (typically to 2-oxoglutarate/ glutamate).…”

Section: Amino Acids As Energy Substrates: Amino-nitrogen Sparingmentioning

confidence: 99%

The problem of nitrogen disposal in the obese

Alemany

2012

Nutr. Res. Rev.

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Amino-N is preserved because of the scarcity and nutritional importance of protein. Excretion requires its conversion to ammonia, later incorporated into urea. Under conditions of excess dietary energy, the body cannot easily dispose of the excess amino-N against the evolutively adapted schemes that prevent its wastage; thus ammonia and glutamine formation (and urea excretion) are decreased. High lipid (and energy) availability limits the utilisation of glucose, and high glucose spares the production of ammonium from amino acids, limiting the synthesis of glutamine and its utilisation by the intestine and kidney. The amino acid composition of the diet affects the production of ammonium depending on its composition and the individual amino acid catabolic pathways. Surplus amino acids enhance protein synthesis and growth, and the synthesis of non-protein-N-containing compounds. But these outlets are not enough; consequently, less-conventional mechanisms are activated, such as increased synthesis of NO z followed by higher nitrite (and nitrate) excretion and changes in the microbiota. There is also a significant production of N 2 gas, through unknown mechanisms. Health consequences of amino-N surplus are difficult to fathom because of the sparse data available, but it can be speculated that the effects may be negative, largely because the fundamental N homeostasis is stretched out of normalcy, forcing the N removal through pathways unprepared for that task. The unreliable results of hyperproteic diets, and part of the dysregulation found in the metabolic syndrome may be an unwanted consequence of this N disposal conflict.

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Section: Amino Acids As Energy Substrates: Amino-nitrogen Sparingmentioning

confidence: 99%

The problem of nitrogen disposal in the obese

Alemany

2012

Nutr. Res. Rev.

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“…a highprotein ration for carnivores, a high-carbohydrate ration for herbivores. In mice (Diamond & Karasov, 1984; Karasov, Solberg, Chang, Hughes, Stein & Diamond, 1985b;Karasov, Solberg & Diamond, 1987), rats (Wolffram & Scharrer, 1984) and carp (Buddington, 1987) intestinal sugar or amino acid transport has been shown to increase reversibly on high-carbohydrate or high-protein rations, respectively. What contributions do such phenotypic responses make to the observed species differences in nutrient transport?…”

Section: Introductionmentioning

confidence: 99%

Genetic and phenotypic adaptation of intestinal nutrient transport to diet in fish.

Buddington¹,

Chen²,

Diamond³

1987

The Journal of Physiology

142

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SUMMARY1. Herbivores have higher rates of intestinal sugar transport and lower rates of amino acid transport than carnivores, if each are studied while eating their respective natural diets. It was unclear whether these species differences involve a genetic contribution, since when omnivores are switched from a high-protein to a highcarbohydrate diet they reversibly increase sugar transport-and suppress amino acid transport. Hence we studied eight fish species of differing natural diets while all were eating the same manufactured diet.2. Na+-dependent L-proline uptake and active D-glucose uptake, measured in vitro by the everted intestinal sleeve technique, followed Michaelis-Menten kinetics. Values of the apparent Michaelis-Menten constant increased with values of the maximal transport rate, probably as a result of unstirred layer effects.3. The ratio of proline to glucose uptake decreased in the sequence: carnivores > omnivores > herbivores. The intestine's uptake capacity for the non-essential nutrient glucose was much higher in herbivores than in carnivores, correlated with species differences in carbohydrate content of the natural diet. Proline uptake varied much less among species, since species with different natural diets still have similar protein requirements.4. Since all species were studied while eating the same diet, these species differences in uptake are not phenotypic but genetic adaptations to the different natural diets.5. In two fish species which normally switch from carnivory towards herbivory or omnivory as they mature, we observe a 'hard-wired' developmental change in intestinal uptake. Larger animals had lower proline uptake relative to glucose uptake than did smaller animals, even though both were being maintained on the same diet in the laboratory.6. Carnivorous fish tend to allocate absorptive tissue to pyloric caeca or a thick mucosa, while herbivorous fish tend towards a long thin intestine.

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“…These have included changing the overall protein, carbohydrate and fat content or more specifically reducing or increasing certain amino acids, hexoses or fatty acids in the food (Lis, Crampton & Matthews, 1972;Karasov, Pond, Solberg & Diamond, 1983;Diamond & Karasov, 1984;Wolffram & Scharrer, 1984;Karasov, Solberg & Diamond, 1987). Several recent reviews have summarized the findings which indicate that there is probably more than one control mechanism involved (Christensen, 1984;.…”

Section: Introductionmentioning

confidence: 99%

Adaptation of glucose transport across rat enterocyte basolateral membrane in response to altered dietary carbohydrate intake.

Cheeseman

Harley

1991

The Journal of Physiology

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1. The effect of changes in the carbohydrate content of the diet on D‐glucose transport across the basolateral membrane of rat enterocytes has been compared with alterations in transport across the brush‐border membrane. 2. Measurement of carrier‐mediated D‐glucose uptake across the jejunal brush border from animals fed a low‐ or high‐carbohydrate diet showed a change in the maximal rate of transport by 7 days which was maintained for 14 days. The low‐carbohydrate diet produced a progressive decline in uptake whereas the high‐carbohydrate diet increased the transport. There was no alteration in the apparent affinity constant as a result of the dietary manipulations and no discernible trend for changes in the passive permeability to glucose. 3. Transport of D‐glucose across the basolateral membrane was also affected by the dietary composition. After 7 days the maximal transport rate was greater in the animals fed the high‐carbohydrate diet. However, while this increase was maintained for 14 days, uptake into vesicles prepared after 2 weeks on the low‐carbohydrate diet showed a return to control levels. 4. A detailed analysis of the time course of these responses showed the effect on basolateral membrane transport to be inducible within 3 days of switching from the low‐ to the high‐carbohydrate diet and could be reversed within a similar period. 5. Kinetic studies using purified basolateral membrane vesicles confirmed that the change in transport was the result of an increase in the maximal transport rate. Analysis of cytochalasin B binding to these membranes showed a parallel change in the number of glucose‐inhibitable binding sites. 6. The component of the diet responsible for these changes was further investigated by replacing the glucose in the high‐carbohydrate food with galactose, fructose, mannose or 3‐O‐methylglucose. Only glucose and fructose produced any significant change in the transport across the basolateral membrane. 7. It is concluded that in response to changes in the carbohydrate content of the diet there are alterations in the capacity for glucose transport across the basolateral membrane of the enterocyte as well as in the brush‐border membrane. The change in transport across the basolateral membrane is best explained by an increase in the number of glucose carriers in this membrane.

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Effect of feeding a high protein diet on amino acid uptake into rat intestinal brush border membrane vesicles

Cited by 33 publications

References 15 publications

The problem of nitrogen disposal in the obese

The problem of nitrogen disposal in the obese

Genetic and phenotypic adaptation of intestinal nutrient transport to diet in fish.

Adaptation of glucose transport across rat enterocyte basolateral membrane in response to altered dietary carbohydrate intake.

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