Leucine and tryptophan metabolism in rats.
نویسندگان
چکیده
The rate of tryptophan metabolism in isolated liver cells from animals fed on a high-leucine diet was greater than for cells from control animals. Leucine inhibited tryptophan metabolism and tryptophan uptake in isolated liver cells, probably by competing for membrane transport. Leucine had no effect on tryptophan 2,3-dioxygenase in vitro. 4-Methyl-2-oxovalerate increased tryptophan oxidation in incubations containing albumin, by displacing bound tryptophan and increasing the availability of the amino acid to the cell. The results suggest that, under extreme conditions, when the availability of tryptophan is low, leucine may be pellagragenic.
منابع مشابه
Effects of excess leucine on growth and tryptophan and niacin metabolism in rats.
The effects of an excess intake of leucine, for a short period (3 to 4 weeks) and a long period (12 weeks), on growth and excretion of tryptophan and niacin metabolites in rats were studied. Excess intake of leucine (4 or 5%) for a short period did not affect increase in body weight or organ weight (liver, kidney and heart) compared with those of rats fed the control diet. Excess intake of leuc...
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متن کاملEffects of a dietary excess of leucine on the metabolism of tryptophan in the rat: a mechanism for the pellagragenic action of leucine.
In order to investigate the mechanism of the pellagragenic action of excess dietary leucine, rats were fed on diets providing a minimally-adequate amount of tryptophan, with no preformed niacin, with and without the addition of 15 g leucine/kg diet. This amount of leucine in the diet has been demonstrated previously to lead to depletion of blood and liver nicotinamide nucleotides. The metabolis...
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عنوان ژورنال:
- The Biochemical journal
دوره 225 2 شماره
صفحات -
تاریخ انتشار 1985