Cystine supplementation sustains plasma mercaptalbumin levels in rats fed low-protein diets more effectively than methionine.
J Clin Biochem Nutr
; 69(2): 122-130, 2021 Sep.
Article
en En
| MEDLINE
| ID: mdl-34616103
ABSTRACT
We recently reported that dietary cystine maintained plasma mercaptalbumin levels in rats fed low-protein diets. The present study aimed to compare the influence of low-protein diets supplemented with cystine and methionine, which is another sulfur amino acid, on plasma mercaptalbumin levels in rats. Male Sprague-Dawley rats were fed a 20% soy protein isolate diet (control group), 5% soy protein isolate diet (low-protein group) or 5% soy protein isolate diet supplemented with either methionine (low-proteinâ+âMet group) or cystine (low-proteinâ+âCyss group) for 1 week. The percentage of mercaptalbumin within total plasma albumin of the low-proteinâ+âMet group was significantly lower than that of the control and low-proteinâ+âCyss groups. No significant differences in the mRNA levels of tumor necrosis factor-α, interleukin-6, interleukin-1ß, and cyclooxygenase 2 in blood cells were observed between the low-proteinâ+âMet and low-proteinâ+âCyss groups. Treatment with buthionine-(S,R)-sulfoximine, an inhibitor of glutathione synthesis, did not influence the percentage of mercaptalbumin within total plasma albumin in rats fed the low-protein diet supplemented with cystine. These results suggest that supplementation with cystine may be more effective than that with methionine to maintain plasma mercaptalbumin levels in rats with protein malnutrition. Cystine might regulate plasma mercaptalbumin levels via the glutathione-independent pathway.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
J Clin Biochem Nutr
Año:
2021
Tipo del documento:
Article
País de afiliación:
Japón